Historic downtown New Orleans in digital 3D. HERITAGE. Cyark is a rather special American NGO. Dedicated to the preservation of historic sites and monuments, it has taken it into its head to create a veritable library, that is to say a collection of 3D digital versions of these same sites. These would then be available to everyone, from an Internet browser, even if their original real version were to be altered, by a natural disaster or the action of men. It is exactly this reflection that led Cyark to digitize New Orleans, hit in August 2005 by Hurricane Katrina - ten years ago. In concrete terms, it was the HERE company that carried out the 3D data survey on site in September 2014, using LIDAR technology, thus providing the NGO with point cloud mapping of the entire city. The latter then selected a series of historic sites (including the French Quarter) likely to be affected by a possible next disaster, i.e. 14.8 km 2 over 900. Cyark first created a 3D model made of triangles, connecting 15 billion points, then overlaid photographic views on it for a final photorealistic rendering. The result is available here on the NGO's website, along with other similar projects. It is also the subject of this video presentation, which recalls the work carried out by the British Postal Museum &Archive on the London Mail Rail: