Like a stone iceberg, Brézé castle boasts an immense hidden section. Beneath the rock lies the largest underground estate of Europe. Its dry moats (18m/60ft deep) take you into a 1km/0.6mi-walk, riddled with passages. Don't miss the entrance, tucked away in an alcove between two walls in the heart of the village. The panoramic view reveals a group of troglodyte homes and vineyards. The period 19C decoration in the apartments is listed.