A 3D computer model of the devastated city has been developed by Nagasaki University with the help of archive photographs, and allows users to explore a 500m (1640 ft) radius around the bomb's hypocentre, The Mainichi newspaper reports . A class of primary school children were the first to try it out, and they didn't just get a visual experience - there's also the sound of footsteps on rubble and wind blowing through the ruins, the paper says.