A video concept like this - detailing the entire newsroom video validation work behind the full coverage of a long-running event - has never been published before by another news agency.

We have created a visual representation of the validation work we carried out during our entire coverage of Turkey’s military offensive into northeast Syria, following the sudden withdrawal of the USA from the region in October 2019.

The significance of this event is key. Turkey’s entrance signaled a new shift in the balance of power in the northeast region that is central to events happening now in Syria. The consequences of this regional power shift are still uncertain.

Our extensive network of independent cameramen on-the-ground, spread across towns and cities in Syria, report each new development for us. This same trusted network covered each unfolding event in the mini-conflict cut by the American void.

What began in our newsroom as charting daily events on Google Earth, based on the reports from our cameramen, developed into an extensive Twitter thread of 100-plus tweets that we kept updated for more than one month.

It consists of the data our cameramen sent to us while on assignment, such as selfies matching the footage they filmed, as well as geo-coordinates or their WhatsApp live location.

We set out a year ago to provide our global clients and the audience a transparent window into the validation and verification process that takes place in our newsroom before we publish videos on our platforms.

As a news agency that provides video to news organisations, we believe this fact-checking process is vital as it provides the audience with a background check on the news they are consuming.

Full transparency is also a crucial component to bolster trust with our clients who expect us to provide them with authentic footage, including from some of the world’s most dangerous and hard to reach areas.

The extensive video validation and verification work seen in this video takes place everyday in our newsroom for almost every video we receive from our entire network of cameramen all around the world.

We planned to have this video ready to publish in February. But due to the rapid outbreak of covid-19, we decided to postpone a launch to coincide with our birthday.

Video context:

The USA announced its departure from the Kurdish-controlled northeast region of Syria on October 7, 2019.

USA withdrawal created a vacuum for Turkey and its allied Free Syrian Army (FSA) militants to launch a military operation to create a 30km deep "safe zone" along the Syrian side of the border.

Turkey, which considers a part of the Kurdish-led alliance a terrorist organisation, said its objective was to secure its border and allow for the resettlement of more than 2 million Syrian refugees, many of whom live in large camps in Turkey.

The Kurds, whom all powers had relied on to defeat the Islamic State, asked the Syrian government and Russia to help stop the Turkish assault.

To end more than a month of fighting, Turkey and Russia agreed to take joint control of the border area.

Here we visualise each moving part of that mini-conflict:

Investigation in-depth:

In this section we explain some of the steps we took to validate significant events that took place during the period from America’s announcement to withdraw on October 7, 2019,  to Turkey and Russia’s first joint border patrol on November 1, 2019.

Throughout this period we customised Google Earth with a map of pinned places that collected our cameramen selfies and their corresponding geopins, as well as typographical elements, like distinct buildings and structures, that we used to validate different videos.

We were also scanning social media for uploads relevant to the story to provide invaluable context and also help us corroborate video. Many of the videos we collected are seen in our video production - their time and date is all verified.

October 7, 2019:

US military forces were seen driving through northeastern Syria on Monday, October 7, after the White House announced in a statement it would pull out troops from the area.

Our cameraman filmed exclusive footage of US forces withdrawing from their position close to Tell Abyad near the Turkey-Syria border.

Before filming, our cameraman sent us this image of him at the position where he filmed US forces assembled along the 712 highway, approx 6 kilometers to the east of Tell Abyad.

In this scene of our footage, showing the US convoy approaching Tell Abyad, we matched elements of the landscape using geopinned open-source images available on Google Maps.

As US forces withdrew from their border positions, civilians held protests across Kurdish areas of north Syria. Our cameraman in Tell Abyad covered a protest that took place on the Monday afternoon.

We got the cameraman's perspective of filming by matching tall visible structures in the distance of our footage. We pinned the visual elements using Google Earth to draw the perspective - the water tower [blue], the communications tower [green] and the minaret [red].

October 8, 2019:

We received a video from our cameraman showing the towns of Tell Abyad and Ain al-Arab/Kobani in Syria, as viewed from the Turkish side in Suruç and Akçakale.

Our cameraman’s location pin placed him within 300m of the crossing into Syria. We see the observation tower on the Turkish side in our footage and in a photo shared on Google Maps.

No photos of this particular crossing point could be found via Google Maps. But a UGC photo dating back to December 2018 confirmed that this structure can be found in the vicinity of Akçakale.

Beyond the border wall where Turkish troops were assembling, the Tell Abyad skyline can be seen.

Another of our cameramen in the area sent us footage of the vacated US military outpost at Tell Arqam, further east near the border at Ras Al-Ain and Ceylanpınar.

Our cameraman sent us an image of him inside the old US base and sent us a geopin on Google Maps, identifying the exact location where he recorded the footage.

We corroborated the location of the US base using wikimapia. We then worked to connect some of the visual elements seen in our footage and get our cameraman’s perspective of filming.

Later on Tuesday, October 8, we were focused on validating more footage from Tell Abyad, as our cameraman there delivered us video of another protest against the looming Turkish military operation.

Our cameraman sent us a selfie and his geolocation from Tell Abyad. We then matched the footage to visual elements available by open-source.

On Wednesday, October 9, as Turkey announced the start of its military operation, we validated more footage from Akçakale. In this footage, we see cars waving Free Syrian Army-aligned Syria flags driving on the Syrian side of the border near Tell Abyad.

Our cameraman sent us his location pin, which placed him on the outskirts of the town, close to the border crossing.

Thousands of people fled the Syrian towns along the border with Turkey. In this footage, we see civilians fleeing from Tell Abyad toward Hasaka province, held by the Kurdish-led Syrian Democratic Forces.

Our cameraman in Tell Abyad sent us another selfie while covering events for us in the town. In his footage there is a road sign that reads: “The town of Tal Abyad thanks you for your visit.”

October 10, 2019:

Footage filmed from the border town of Ceylanpinar inside Turkey, shows smoke rising from locations hit in Ras al-Ain on Thursday, October 10, as well as a convoy of Turkish military vehicles moving into the area.

Our cameraman captured airstrikes and artillery shelling hitting Ras al-Ain as Turkey's operation got underway. Our cameraman sent us a selfie from his position and we took a screenshot from his live broadcast.

Several people were reportedly killed in the northern Syrian city of Qamishli on as 'Operation Peace Spring' targeted the region for the second day.

Footage from our cameraman in Qamishli showed families mourning victims. Our cameraman captured selfies on-scene and we analysed the metadata of his raw video file.

October 11, 2019:

More US forces were seen about 30km outside Tell Abyad, some 5 days after withdrawing from the border area.

Our footage from Friday, October 11, shows armoured vehicles 40km from the former Lafarge cement factory then used as a US military base.

Our cameraman sent us a selfie from the location where US forces were assembled. The road sign gave us the location by measuring the distance on Google Maps against the information provided by our cameraman.

Our cameraman’s footage showed the US forces travelling toward the US military base at the former Lafarge Cement plant.

We compared the site against old news reports:

October 12, 2019:

Kurdish forces fought gun battles with the Turkish-aligned Free Syrian Army - also known as the Syrian National Army - in the countryside west of Tell Abyad in north-eastern Syria, as seen in our undercover footage filmed on Saturday , October 12.

Our cameraman travelling with the SNA sent us his location - placing him 8km outside Tell Abyad. We matched his location on Google Maps, paying close attention to road and street line patterns in both.

We used a Tweet from a journalist embedded with Turkish forces to help corroborate the information we received for our cameraman - this gave us the location of the clashes. Once confirmed, we set about determining a precise geolocation.

In one of the shots in our video, we see two FSA fighters in position near two low structures with an electric pole in between them. We got our cameraman’s position and distance to the structure which corroborate with the story and images he sent to us.

Turkish-aligned FSA forces advanced into Tell Abyad on Sunday, October 13. Our footage shows fighters patrolling the town on foot and with armoured vehicles, streets deserted and buildings left empty.

Images in our footage, sent by our cameraman on-the-ground, show a sign post that reads: Tell Abyad Hospital. We also matched the same communications mast in our footage to images geotagged to Tell Abyad on Google Maps.

October 13, 2019:

Syrians in Qamishli celebrated on Sunday, October 13, at the announcement that Syrian troops would be deployed to the north of Syria.

Our footage shows people dancing in the streets and waving Syrian flags.

We received a location pin and a selfie from our cameraman in Qamishli, which matched scenes in the footage we received from him.

October 14, 2019:

On Monday, October 14, Syrian soldiers entered Tal Tamr in the countryside of Hasakah Governorate, after reaching a deal with Kurdish groups to help defend the north of Syria from the ongoing Turkish incursion.

Our cameraman in the area sent us an image of a road sign visible when entering Tal Tamr from the west. We measured the distances seen in the road sign using Google Maps direction feature - all the distances matched.

Turkish forces were approaching the town of Manbij on in a bid to oust Kurdish-led fighters from the north-eastern Syrian city.

We gathered an Instagram Stories post shared by a Turkish soldier that was geotagged as Manbij - we matched its background to that seen in a video posted on a Facebook page aggregating Turkish military content.

Video: https://www.facebook.com/watch/?v=252082549046172

Like this soldier, we found many other Turkish soldiers geo-tagging their Instagram uploader to areas in northeast Syria, unintentionally documenting the incursion.

The US Army and the Syrian Army were seen driving past each other on the road linking Manbij and Kobani, on the M4 highway in north-eastern Syria.

Our cameraman sent us a selfie with Syrian army soldiers assembled in the background - in his footage we see both the flags of the US and Syria. He also sent us a geopin of where this encounter took place.

October 15, 2019:

Residents in Manbij celebrated on the streets on Tuesday, October 15, following the announcement that the Syrian army were arriving to the city after reaching a deal with Kurdish groups.

Our cameraman also sent us his WhatsApp live location - it placed him at the municipality in the center of Manbij. We matched his footage against a Twitter video of the same event & found a corresponding image of the municipal building.

The Syrian army reached the outskirts of Manbij on October 15 - not entering the city but gathering at a school building some 7km east of the city. Our footage shows local residents & soldiers mixing together.

Our cameraman in Manbij sent us his selfie & WhatsApp live location as he filmed the Syrian army deployment. We reviewed his location on Google Maps and next switched to Google Earth to geolocate the exact buildings seen in our footage.

Using Google Earth we matched the building's main door staircase [red], the positioning of the gated entrance [green], the smaller square-shaped building [orange] and the vertical positioning of the main building [purple].

We next validated footage taken on Tuesday from inside the former US military base near Manbij.

The location of the former US base is 12km west of Manbij. We matched our footage against the 3 large communications towers - 1 inside the base & 2 more outside the base parameter wall. We then worked out the exact location of filming.

Location: http://wikimapia.org/#lang=en&lat=36.493233&lon=37.826657&z=16&m=w

Russian military police were seen patrolling Manbij on Tuesday, October 15, in footage released by the Russian MoD. Footage shows Tiger armoured cars traversing through Manbij city.

The Russian MoD released the footage on Wednesday, October 16, but we discovered it was filmed a day previous because our cameraman in Manbij sent us footage of the exact same event, along with his live location. We made an exact match of the sequence of vehicles.

The Russian vehicles entered Manbij from the west roundabout (coming from the direction where the former US base is located ). We see straight-angle pavement work around the monument, with four pavements at equal angles.

Location: https://www.google.com/maps/place/36%C2%B030'58.2%22N+37%C2%B054'23.4%22E/@36.516179,37.9055674,394m/data=!3m2!1e3!4b1!4m14!1m7!3m6!1s0x1531aaf40861e571:0x632a18d36ef51a6d!2sManbij,+Syria!3b1!8m2!3d36.5352848!4d37.9678652!3m5!1s0x0:0x0!7e2!8m2!3d36.5161788!4d37.9064962

We also saw the armound cars pass the Memorial Park roundabout, travelling west out of Manbij. This told us that the footage was not edited in sequence.

Location: https://www.google.com/maps/place/36%C2%B031'21.9%22N+37%C2%B055'48.5%22E/@36.522737,37.9279373,882m/data=!3m2!1e3!4b1!4m14!1m7!3m6!1s0x1531aaf40861e571:0x632a18d36ef51a6d!2sManbij,+Syria!3b1!8m2!3d36.5352848!4d37.9678652!3m5!1s0x0:0x0!7e2!8m2!3d36.5227371!4d37.9301261

We also saw the Russian armoured vehicles turn left - travelling north - at a boat monument roundabout in central Manbij.

Location: https://www.google.com/maps/place/36%C2%B031'33.5%22N+37%C2%B056'42.5%22E/@36.5259581,37.9445838,225m/data=!3m2!1e3!4b1!4m14!1m7!3m6!1s0x1531aaf40861e571:0x632a18d36ef51a6d!2sManbij,+Syria!3b1!8m2!3d36.5352848!4d37.9678652!3m5!1s0x0:0x0!7e2!8m2!3d36.525957!4d37.9451313

October 16, 2019:

We next validated cellphone footage recorded from outside the former US military base in Tell Beyder. Our cameraman recorded the footage on Wednesday, October 16.

Our cameraman also sent us a selfie and a shorter cellphone clip taken from directly outside the former US base. In this clip we can see a row of six large steel cylinders, which are present on the site of the vacant base.

The cameraman’s selfie shows the cylinders too. We also matched exactly where our cameraman recorded his short UGC clip - again using the cylinders as our point of reference.

Location: https://www.google.com/maps/place/36%C2%B044'31.3%22N+40%C2%B034'31.8%22E/@36.7420393,40.5733113,926m/data=!3m2!1e3!4b1!4m14!1m7!3m6!1s0x154afc4fda40955b:0xfe50fa8565ae40a9!2sTell+Beydar,+Syria!3b1!8m2!3d36.7386561!4d40.5864355!3m5!1s0x0:0x0!7e2!8m2!3d36.7420354!4d40.5755002

We received more footage of another former US base on Wednesday, October 16, at the site of a ruined airbase at Al-Tabqa. Our cameraman travelling with the Syrian army recorded the soldiers at the base for the first time in six years.

We received a selfie from our cameraman matching an exact scene in our footage - we matched the identities of soldiers seen in the background of the selfie. The location of the former US base at Al-Tabqa is below.

Location: https://www.google.com/maps/place/35%C2%B045'23.6%22N+38%C2%B034'02.1%22E/@35.7565603,38.5650463,938m/data=!3m2!1e3!4b1!4m14!1m7!3m6!1s0x1530b19093ac7b4d:0x831baeb3e4487ba5!2sAl+Tabqah,+Syria!3b1!8m2!3d35.838063!4d38.5375358!3m5!1s0x0:0x0!7e2!8m2!3d35.7565565!4d38.5672349

Later on Wednesday, our cameraman travelling with the Syrian army near Kobane filmed soldiers entering the key border town. Our cameraman sent us an image, taken with Syrian soldiers 10km outside Kobane.

Our video shows troops entering Kobane from the south, passing the domed roof of this building near a cemetery, visible on Google Maps satellites on the Kobane-Aleppo Way.

At the top of Kobane-Aleppo Way, as the road becomes part of the city, a building with a distinctly shaped roof can be found. We also geolocated the location of the monument representing the gate to the city.

Location: https://www.google.com/maps/place/36%C2%B052'57.0%22N+38%C2%B020'26.0%22E/@36.882498,38.3400198,219m/data=!3m2!1e3!4b1!4m14!1m7!3m6!1s0x15315e51f7b65f5f:0xe0fcf5afc880bd73!2sKobane,+Syria!3b1!8m2!3d36.8903434!4d38.3500108!3m5!1s0x0:0x0!7e2!8m2!3d36.8824983!4d38.3405673

October 18, 2019:

Thousands of Kurdish protesters rallied in Kobane on Friday, October 18, to protest against Turkish military action in northern Syria and the resulting civilian death toll.

Before filming, our cameraman sent us this image of him at Resistance monument - Qada Arîn Mîrkan - where protesters were gathered.

In this scene of our footage - showing the Resistance monument - we matched the location of the cameraman & monument using geopinned open-source images available on Google Maps.

October 19, 2019:

The Syrian army entered Qasr Yalda northwest of the town of Tall Tamr on Saturday, October 19, a location formerly used by the US military as an operating base in the region.

Our cameraman sent us an image and his geolocation from the former US base. We then matched the footage to visual elements available by open-source.

Location: https://zoom.earth/#view=36.658892,40.347988,19z/layers=labels,crosshairs

October 20, 2019:

US forces started to withdraw from their largest base near Sarrin in northern Syria on Sunday, October 20, after the US confirmed they would leave for western Iraq to continue fighting ISIS factions.  

Our cameraman sent us a selfie showing a large US convoy. He also sent us his geopin, placing him close to the town of Tell Brak.

Location: https://www.google.com/maps/place/36%C2%B046'00.6%22N+40%C2%B054'27.3%22E/@36.777496,40.9109451,1001a,35y,196.5h,55.05t/data=!3m1!1e3!4m5!3m4!1s0x0:0x0!8m2!3d36.7668363!4d40.907569?hl=en-US

Footage filmed on Sunday, October 20, shows civilians, who fled Ras al-Ain due to Turkey's continuing military offensive, passing through a checkpoint near Tall Tamr in northern Syria.

Our cameraman sent us a selfie matching his footage. He also sent us a geopin from the vicinity of the checkpoint at Tall Tamr - we used a scene showing road signs to corroborate his location.

Our cameraman on-the-ground spoke with a humanitarian with the Free Burma Rangers, who also published a brief account of his work while in Ras al-Ain helping to get civilians and wounded away from the frontline.

October 21, 2019:

On Monday, October 21, US military vehicles were hit with rocks and vegetables by local residents as they withdrew through the northern Syrian city of Qamishli.

This video was recorded by one of our local media partners. We checked this footage for existing archive content and, once satisfied, we geolocated the exact position of the US vehicles in Qamishli.

October 23, 2019:

Footage filmed on Wednesday, October 23, shows Russian military vehicles patrolling the streets of Manbij. Turkey and Russia had made a deal to establish a ‘safe-zone’ in north-east Syria and to carry out joint border patrols.

Our cameraman in Manbij had been following events in the city since the withdrawal of US troops from the region on October 7.

As per all his footage sent to us, he sent us a selfie from the scene, which we matched to his footage.

Our cameraman also sent us extra cellphone footage of the Russian military vehicles patrolling the city. In this cellphone footage we see the Russian patrol moving eastward, out of Manbij.

In our cameraman’s cellphone footage, we see the Russian military vehicles pass Memorial Park roundabout. Our team had Memorial Park roundabout pinned on Google Earth & we also cross-checked against open-source Google Maps images.

We received more footage on Wednesday, October 23, of a Russian military convoy patrolling north-eastern Syria - this footage shows a military patrol east of Kobane.

Our stringer sent us a selfie with one of these Russian military vehicles in the background - the same ones that appear in our video. We matched the text on the vehicle to that seen in the selfie: it reads 'military police' in both Russian and Arabic.

We also received our stringer's position on-the-ground. This placed him between two distinct structures - a communications tower and a watchtower - both of which can be seen in our footage.

Location: https://www.google.com/maps/place/36%C2%B053'31.4%22N+38%C2%B015'23.4%22E/@36.8920489,38.2545,894m/data=!3m2!1e3!4b1!4m14!1m7!3m6!1s0x0:0x0!2zMzfCsDAzJzA1LjgiTiA0McKwMTMnMTYuNiJF!3b1!8m2!3d37.0516205!4d41.2212715!3m5!1s0x0:0x0!7e2!8m2!3d36.8920452!4d38.2565073?hl=en

Later on Wednesday, October 23, we received footage of the aftermath of a car bomb in the centre of Qamishli - one of a string of explosions to hit the region. ISIS later claimed responsibility for the explosion.

Our cameraman in Qamishli sent us a selfie from the site of the bomb - the position where he filmed his footage - as evidence that he was on-site at the location.

The bomb exploded close to the Zine El Abidine Mosque, which we see in the background of our cameraman’s selfie.

Location:  https://www.google.com/maps/place/Zine+El+Abidine+Mosque/@37.0514937,41.2211865,248m/data=!3m1!1e3!4m13!1m7!3m6!1s0x0:0x0!2zMzfCsDAzJzA1LjgiTiA0McKwMTMnMTYuNiJF!3b1!8m2!3d37.0516205!4d41.2212715!3m4!1s0x400a0f7c21768e8b:0xa8df63e068546a2b!8m2!3d37.0518115!4d41.2225807?hl=en

October 27, 2019:

On Sunday, October 27, US President Trump said ISIS leader al-Baghdadi had been killed in a US special forces operation in Barisha, Idlib.

Read our spotlight verification Twitter thread here on how we covered it:

October 28, 2019:

US military vehicles were filmed on Monday, October 28, patrolling an oilfield in Al-Hasakah province. This move came after an announcement by President Trump that the US military planned to strengthen its presence in eastern Syria to secure oilfields.

Our cameraman sent us his position via MapsMe - this placed him at an oilfield outside the town of Gunde Aror. We were able to independently match his position to our video via Google Earth satellite imaging.

We corroborated our location using a content panel curated by the Energy Consulting Group on Syria's energy sector. We used its information and some of the Group’s maps to help us corroborate the presence of the oil plant seen in our footage.

Map: http://energy-cg.com/MiddleEast/Syria/Syria_Turkey_Kurds_ChessBoard_Start_Image1x1_Oct19_EnergyConsutlingGroup_web.png

October 29, 2019:

Running along the Turkish-Syrian border, our cameraman filmed Russian military police on the move on Tuesday, October 29, between Ad Darbasiyah - Amuda - Qamishli.

In his footage, the vehicles pass several roundabouts in Amuda and Qamishli with distinctive designs. We were able to match these to images shared publicly within Google Earth.

October 30, 2019:

Clashes broke out at Tal Tamr on Wednesday, October 30,  between Turkish-backed forces and Kurdish forces, as well as Syrian government forces. Our footage shows thick black smoke rising from around the town.

A journalist working from northeast Syria broadcast a dispatch on Facebook Live from Tal Tamr. We spoke with her and she filmed footage of events for us - we traced her extensive digital footprint reporting from the region.

Live video: https://www.facebook.com/watch/live/?v=1147952072065339&ref=watch_permalink

October 31, 2019:

Footage filmed on Thursday, October 31, shows a convoy of Russian military police meeting with Turkish military at the border crossing in al-Darbasiyah.

Our cameraman sent us a selfie from the scene and we were also able to identify him in other media reports from the area, confirming to us that he was on-scene and his report is authentic.

News report: facebook.com/NPA.SYR/photos/pcb.1170191076508796/1170190916508812/?type=3&theater

The meeting took place at the same location where a purported mortar incident had taken place. It’s the border-crossing in al-Darbasiyah.

Location: https://www.google.com/maps/place/37%C2%B004'38.6%22N+40%C2%B038'47.0%22E/@37.0778606,40.6474106,633m/data=!3m1!1e3!4m5!3m4!1s0x0:0x0!8m2!3d37.077392!4d40.6463778?hl=en-US

We can see the shadow of the large Turkish flag at the border, matching with the visuals we see in our video. We used other news org footage to corroborate the prominent cylinder structures on the Syria-side of the border.

At least eight people were killed and several others injured on Thursday, October 31, in a car bomb explosion at a local market in Afrin. Our footage shows the aftermath of the explosion.

Our cameraman sent us a selfie and the location of the explosion. He told us the car bomb exploded in the main market - Souq Al Hal - in Afrin.

Location: https://www.google.com/maps/place/36%C2%B030'35.8%22N+36%C2%B052'20.3%22E/@36.5099483,36.8701126,997m/data=!3m2!1e3!4b1!4m14!1m7!3m6!1s0x152f93f987fca169:0xedd9b3393ae9421b!2sAfrin,+Syria!3b1!8m2!3d36.5122781!4d36.8653891!3m5!1s0x0:0x0!7e2!8m2!3d36.5099438!4d36.8723044

November 1, 2019:

On Friday, November 1, Russia and Turkey began conducting joint patrol of the border area near al-Darbasiyah. Our footage shows military vehicles on joint patrol through the Al Hasakah countryside.

Our cameraman sent us his on-scene selfie, taken roughly 10km east of al-Darbasiyah.

Location: https://www.google.com/maps/place/37%C2%B002'39.3%22N+40%C2%B033'53.7%22E/@37.0424658,40.5561659,2888m/data=!3m1!1e3!4m6!3m5!1s0!7e2!8m2!3d37.0442574!4d40.5649084

In our footage we can see Turkish vehicles pass through a small village, south of the meeting point at the border, where there is a park dedicated to a martyred Kurdish fighter.

Location: https://www.google.com/maps/place/37%C2%B000'20.9%22N+40%C2%B035'42.9%22E/@37.0058188,40.5937942,923m/data=!3m2!1e3!4b1!4m14!1m7!3m6!1s0x1518e6dc413cc6a7:0x877546f4882af620!2sSyria!3b1!8m2!3d34.802075!4d38.996815!3m5!1s0x0:0x0!7e2!8m2!3d37.0058161!4d40.5952407