Mendukilo Caves

The language of minerals beneath the surface

Here, where the mineral matter holds the silence of the centuries and the karst landscape opens up into the bowels of the Sierra de Aralar, time dissolves beneath the surface. In the Mendukilo Caves, one can sense the constant pulse of water dripping onto the limestone and the whisper of an underground life that reveals itself unhurriedly, allowing the mountain’s identity and the memory of its galleries to emerge before those who choose to venture into its depths. It is a realm of absolute stillness, where the traces of ancient shepherds and the solidity of the stalactites and stalagmites coexist in a mineral harmony that is revealed step by step. 

Mendukilo Caves – general information

They are situated in the lands of the Astitz Council, in the heart of the Aralar Range, forming an open window onto the last territory yet to be explored: the underground world . Their identity is rooted in a landscape of reef limestone dating back between 114 and 96 million years.

They extend for between 700 and 800 metres in length and have a vertical drop of 90 metres, with an entrance situated at an altitude of 750 metres. Inside, they harbour a variety of geological formations such as stalactites, stalagmites, flowstones and gours, as well as a troglobitic fauna that inhabits their galleries exclusively. Life beneath its roof is maintained at a constant temperature of 8–9 °C, with humidity close to saturation. 

How to get to the Mendukilo Caves?

It is easy to reach the site from the centre of Lekunberri.

• Access by road: From the A-15 motorway (Pamplona-Irún), take the Lekunberri exit to join the NA-7500 road towards Madotz.
• Final stretch: After travelling 5 kilometres and passing through the village of Alli, a track branches off leading directly to the entrance of the cave, situated 1.5 km from Astitz.

What to do at the Mendukilo Caves?

Beneath the mountain range lies a landscape where geology and pastoral heritage intertwine in silence.

• Exploring the main chambers: A 540-metre guided tour takes you through three key areas: Artzainzulo (shepherds’ shelter), Laminosin (the chamber of lakes) and Herensugearen Gotorlekua (the dragon’s lair).
• Caving adventure: For those seeking a more immersive experience, activities are organised to descend to lower levels and discover formations off the beaten track.
• Interpretation centre: A space to understand the geology of the Sierra de Aralar and the historical use of these caves.
• Wildlife observation: An area where the presence of bats and other cave-dwelling species can be recorded, in a respectful manner, within protected areas.