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Karrantza, a valley with exceptional rural scenery, also has a significant industrial heritage, highlighted by the former Dolomitas factory, now a museum. This industrial site is surprisingly linked to Pozalagua Cave, a cavern that holds the world record for helictite formations.
The route begins with a guided visit to the Dolomitas Museum in the Ambasaguas neighbourhood, a place that will transport us back to the industrial peak of Bizkaia. The factory, founded in 1947, produced refractory bricks for Altos Hornos de Vizcaya using dolomite extracted from the Donosa quarry. The quarry was located in Ranero, in what is now the Armañón Natural Park, next to the Pozalagua cave.
An aerial tramway was used to transport the ore from the quarry to the unloading station (now the museum, with Monument category). It was the last of its kind to operate in Bizkaia, and even today we can see the system of giant pulleys that powered it manually.
The museum reminds us of the role played by the Dolomite Factory in the production of sintered dolomite, capable of withstanding the high temperatures of metallurgical furnaces. Thanks to the bricks made from this mineral, it was no longer necessary to constantly shut down the furnaces for repairs.
It is striking to see how that industrial complex blends into an extremely beautiful natural setting: the Armañón Natural Park, a karst landscape dotted with forests and an underground labyrinth of caves and sinkholes. The Parketxea (the park’s visitor centre) occupies the site of the former ore crushing and loading station, now turned into a viewing point overlooking the valley through which the dolomite was transported by aerial tramway.
Just a few metres away lies the Pozalagua Cave, discovered by chance during mining work after a dynamite charge blew a hole in the mountain. Inside, it houses the world’s largest concentration of helictites, formations that grow in all directions, creating a mesmerising mosaic.
The cave tour winds its way through columns, stalactites and a dried-up lake, from which thousands of helictites spring up at random. The tour ends at a viewing point offering a glance of the huge scale of this ‘underground cathedral’.
Outside, in front of the cave, the old quarry has been transformed into an amphitheatre carved directly into the limestone rock. Its massive walls reveal the bare dolomite, so dazzling that it looks like marble. The auditorium hosts concerts and performances, such as those of the famous Pozalagua Festival.
Karrantza surprises us at every turn. Amidst the apparent peace of the Biáñez neighbourhood, a 15-minute drive from the cave and just 5 minutes from the Dolomitas Museum, we can see panthers, lynxes, deer, kangaroos and guanacos… They are the inhabitants of BBK Karpin Fauna, a wildlife rescue centre for animals that have fallen victim to illegal trafficking or hunting, or have been abandoned and can no longer be returned to their natural habitat. Here they find a safe home and the care they need.
Karrantza is also an excellent place to stop off and discover the Enkarterri flavours. In this valley, the cuisine is a tribute to the land. The restaurants offer a culinary experience centred on charcoal-grilled meats, artisan cheeses, locally produced honey and vegetables from their own gardens. It’s the perfect way to round off your trip or continue your journey on a high note.
To top it all off, it’s well worth a visit to nearby Lanestosa, the smallest town in Bizkaia, which was once an important trading hub between the coast and the town itself. From those days, it retains its medieval old town, which preserves the original 13th-century layout intact, with its cobbled streets, the old bridge, ancestral houses, mansions built by returning emigrants, and other places of interest, such as the old lime kilns.
Explore the Karrantza Valley on foot or in a 4WD with Carrantia. This customized itinerary takes you through endless forests, past prehistoric dolmens and natural arches overlooking the abyss, and offers opportunities for birdwatching. A unique experience to connect with nature in one of the best-preserved areas of the Basque Country.
Discover with Leykatur the story of the ‘Indianos’ who returned to Karrantza after making their fortunes in the Americas. The tour of the Concha neighbourhood showcases their luxurious mansions and reveals the origins of their fortunes, their charitable works and the stories behind a legacy that transformed the landscape of Enkarterri.
Within the Armañón Natural Park, the Casa Pallotti spa is the ideal retreat to unwind. Its facilities combine traditional spa treatments with modern wellness techniques, thanks to its waters’ properties. A setting surrounded by nature, perfect for nurturing both body and mind.
Karrantza is 55 km from Bilbao and 68 km from Santander, an hour’s drive from both cities. It is advisable to travel by car, as public transport to the valley is infrequent.
See Bizkaibus lines
Karrantza (43.238854, -3.357937)
FEVE Narrow-gauge Railways / Timetables and fares / Timetable enquiries Visit website
Dolomites (43.239499, -3.358149) See on Google Maps
Pozalagua Cave (43.260131, -3.385324) See on Google Maps
Beroutes Visit website
Urgebi Bikes Visit website
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Karrantza
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