🏰 The Templar town with a hidden underground 'twin'
Medieval hilltop settlement in Italy with an extensive subterranean network
📌 Fast Facts
- Location: Marche region, central Italy, near Ancona
- Coordinates: 43.48°N, 13.48°E
- Underground network: Extensive tunnel system beneath historic center
- Architecture: Medieval and Renaissance structures from 13th century onward
Osimo is a medieval hilltop town in the Marche region of central Italy that contains an extensive network of tunnels and chambers running beneath its streets. The subterranean system connects major palaces and religious buildings, effectively creating a second city underground whose purposes and origins remain partly obscure. As of 2026, portions of the tunnel network are accessible to visitors through guided tours, though the full extent and layout of the underground passages continue to be ...