The more hidden but by no means the least known part of the Basque Country lies deep in its bowels and goes back thousands of years. Santimamiñe, Pozalagua, Arrikrutz and Ekainberri are the names of the four best-known and most visited cave sites. Before anything, a word of advice. It is a good idea to book in advance because their historic importance and excellent state of conservation make them very popular.
The renowned ethnologist and archaeologist, André Leroi-Gourham, claims that the Ekain cave paintings, in the Gipuzkoan district of Deba, have the most perfect set of horses ever seen in all quaternary art. It is a UNESCO World Heritage of Site. Due to its importance and its fragility, it was necessary to build Ekainberri, a replica that can be visited. This is one of the principal European prehistoric sanctuaries and the jaw-dropping beauty of the paintings takes you back in time.
Arrikrutz cave was opened to the public in 2007. Located close to the Sanctuary of Arantzazu, under the Aizkorri massif, it is one of the caves from the Gesaltza-Arrikrutz karst complex, with 14 kilometres of underground galleries. During the visit, you descend 55 metres into the bowels of the earth, until reaching gallery 53 where the sight of the underground river Aldaola will cause an inexplicable feeling. The huge stalactites are also visible together with finds such as the complete skeleton of a lion from the caverns. It is a magical visit for adults and children alike.
Right in the heart of Bizkaia is Santimamiñe cave with paintings over 14,000 years old in which it is possible to clearly distinguish the figures of bison, horses and bears. They also contain a huge number of stalagmites and stalactites.
Lastly in the westernmost part of Bizkaia is Pozalagua cave. This contains the highest concentration in the world of eccentric stalactites, that is, ones that defy gravity creating seemingly impossible shapes in the air that will leave you dumbstruck. This cave is 125 metres long and has four spectacular chasms, 40 metres deep.