These are some of the first modern 360-degree photos.

Taken in between 1997 and 2001 in Ground Zero, they recently piqued the interest of a team of French documentary-makers.

From the images, a production company created a short film of a special kind — an immersive experience.

Paris-based Targo pursued a project to commemorate the 20th anniversary of 9/11 in virtual reality (VR).

Director Chloé Rochereuil found the idea while searching for the first 360 photos taken in the world.

“We noticed that there were pioneering photographers of virtual reality and 360-degree photos, who had taken photos of the Twin Towers, from the square, at the bottom of the towers, in 360, and while digging in the archives online , we realised that there were dozens of them. So we started to look for them to recover these photos and create a virtual reality experience to be in New York again, with these Twin Towers. It was the starting point of the documentary,” says Rochereuil.

Partnering with Facebook’s VR subsidiary Oculus, they built 3D models of the towers, from offices to the lobby — efforting to make every element and its placement as accurate as possible.

“The rationale of this documentary, it was to be extremely precise on 3D reconstructions, we worked a lot to search in archives to recover documents, maps, videos and photos to allow us to be as precise and journalistically accurate and close to what the Twin Towers looked like in 2001, during the attacks,” says Rochereuil.

The documentary retraces the story of Genelle Guzman-McMillan, the last survivor pulled out of the rubble, where she was stuck for 27 hours.

She was interviewed using special cameras filming 360 degrees around them.

“The plane hit the building. I felt like ‘Oh my god, we’re gonna die.’ I was so scared, I just wanted to get out. I made it to the 13th staircase, and that’s when the rumble, and then the walls, the darkness, everything just come crumbling,” says Guzman-McMillan in the documentary.

The documentary took almost a year to produce, with most of the time dedicated to the technological aspect of it, which included a lot of research.

“The starting point for us, for all the remodelling, was to begin with architectural blueprints of the World Trade Centre,” says Victor Agulhon, Producer of “Surviving 9/11, 27 hours under the rubble” and Co-Founder of Targo.

“So we recovered the original blueprints used to built it, and thanks to them we recreated all the models, all the volumes, all the exact dimensions of the building. Then, from Genelle’s testimony, we placed all the offices, the ones of her bosses, of her colleagues, really recreating her work environment. And to give it this photo realistic look, this ambiance of the World Trade Centre in 2011, we used archive photos, photos from her colleagues which allowed us to recreate the colour, the layout of the cubicles, and ultimately the ambiance of the office in 2001.”

For the rubble, the team scanned artefacts in 3D, like beams from the 9/11 Memorial Museum in New York City.

This piece of metal was scanned to be recreated virtually and make the debris as accurate as possible.

The same attention to detail went into the restoration of the old photos.

“So as soon as we recovered the negatives of the photos we had to work on them to turn them into positives and clean them,” says Agulhon.

“Once that first step was over,  we had to assemble them. So it’s when we have to make every bit of the image match each other to have a 360-degree panoramic view. And sometimes, in this case for example, some elements of the photo are missing (to make a 360-degree photo), which need to be recreated. And that’s a very meticulous job of recreation from archive photos to recreate a complete 360-degree image. Once we’ve done this, the remaining job is to turn it into virtual reality, meaning turning it into 3D, and projecting it at 360 degrees so that the viewer finds themself at the foot of the Twin Towers.”

The same process was used for each photo, here the debris seen from above.

Facebook was drawn to the project as part of the “VR for good” initiative launched by its subsidiary Oculus, a program designed to fund VR projects, especially from students and non-profits.

“VR has been frequently referred to historically as an empathy machine. And I think this piece really shows how powerful that can be in terms of bringing or letting viewers feel empathy for Genelle and as they experience her story. And so, it’s really important to provide a platform for stories like this and in this particular case, a chance to reflect on the lives lost during the 9/11 attacks,” says Eric Cheng, Executive Producer of “Surviving 9/11, 27 hours under the rubble” and Immersive Media Lead at Facebook Reality Labs.

The studio Targo insists that the documentary is not meant to relive the traumatic attacks but to dive into the memories of a survivor.

“Surviving 9/11, 27 hours under the rubble” was released on 7 September and is freely available to Oculus VR headsets owners.