San Adrian

San Adrian is a natural passage carved through limestone rock that connects two Spanish provinces across the Aizkorri mountain range. Inside the tunnel stands a chapel, and visitors follow a marked hiking path that takes roughly one hour to traverse.

The tunnel has functioned as a trade and pilgrimage route since the Bronze Age, linking the Spanish plateau with territories to the north. Medieval travelers made it an essential stopping point on their journeys across the mountain passes.

The chapel inside the tunnel has drawn pilgrims and travelers for centuries, serving as a place where people pause to reflect during their journey. The space represents the intertwining of spirituality and passage through the mountains that shaped the region.

The trailhead is clearly marked from the parking area at Otzaurte, making it easy to find your way without confusion. Sturdy hiking shoes are recommended due to the uneven rocky terrain and occasional wet conditions inside the passage.

A medieval inn once operated within the natural chamber of the tunnel, offering shelter and food to travelers crossing the mountain passage. This resourceful use of the rock formation reveals how people adapted the landscape to serve daily needs.