This picture was taken at Sponza, by Cale Flanagan, who says of his experience:
The model of the Sponza atrium (made by Marko Dabrovic and Frank Meinl) is a test scene for global illumimation / radiosity. This is an adaption for Sansar with slight fixing and enhancements.
Sponza is a cool model. I have it too. Here is a render I did with Sponza. https://www.flickr.com/photos/40810188@N02/4241110376/