Richard points me to the Stanford Digital Forma Urbis Romae Project. “This is one of my favourite map stories,” he says.

This enormous map, measuring ca. 18.10 × 13 meters (ca. 60 × 43 feet), was carved between 203-211 CE and covered an entire wall inside the Templum Pacis in Rome. It depicted the groundplan of every architectural feature in the ancient city, from large public monuments to small shops, rooms, and even staircases… .

The Severan Marble Plan is a key resource for the study of ancient Rome, but only 10-15% of the map survives, broken into 1,186 pieces. For centuries, scholars have tried to match the fragments and reconstruct this great puzzle, but progress is slow — the marble pieces are heavy, unwieldy, and not easily accessible.

Now, computer scientists and archaeologists at Stanford are employing digital technologies to try to reconstruct the map.