spmallick writes "Researchers at the University of Washington, in collaboration with Microsoft, have recreated the city of Rome in 3D using images obtained from Flickr. The data set consists of 150,000 images from Flickr.com associated with the tags 'Rome' or 'Roma,' and it took 21 hours on 496 compute cores to create a 3D digital model. Unlike Photosynth / Photo Tourism, the goal was to reconstruct an entire city and not just individual landmarks. Previous versions of the Photo Tourism software matched each photo to every other photo in the set. But as the number of photos increases the number of matches explodes, increasing with the square of the number of photos. A set of 250,000 images would take at least a year for 500 computers to process... A million photos would take more than a decade! The newly developed code works more than a hundred times faster than the previous version. It first establishes likely matches and then concentrates on those parts."