Fort de Pré-Giraud is a Cold War–era Swiss Army fortress built inside a mountain above Vallorbes, disguised externally as a large Swiss chalet. The deception is convincing from a distance — only the unusual size and the lack of garden furniture give it away. Inside, a labyrinth of tunnels and chambers contains artillery positions, living quarters for over 100 soldiers, a hospital, a kitchen, ammunition stores, and a diesel generator that could run the fort indefinitely off the grid.
The fort is open for guided tours, which take you through the full network of tunnels and explain the Swiss Army's strategy for defending the French border approach. Much of the original equipment is still in place — the artillery pieces, the bunk rooms, the communications equipment frozen at some point in the late 20th century. It is a remarkably complete preserved example of Swiss Cold War military infrastructure. Tours last about 90 minutes and are available in French, German, and English by arrangement.