Cardona salt mountain

Muntanya de Sal (Salt Mountain) in Cardona is one of Catalonia's strangest geological landmarks — a hill made almost entirely of rock salt, rising above the Cardener river valley roughly 100 km northwest of Barcelona.

How did a mountain of salt form?

The story begins around 5.6 million years ago, when the Mediterranean Sea was cut off from the Atlantic Ocean and much of its water evaporated, leaving behind a thick layer of salt. Over the following three million years, that layer was buried under rock and clay, until tectonic activity pushed it back up to the surface at Cardona, forming a mountain of nearly pure salt. Remarkably, the process hasn't stopped — ongoing pressure beneath the surface means the mountain is still slowly growing today. It's one of the few places on the planet where salt deposits exist both underground and exposed on the surface at once.

From Neolithic quarrying to industrial mining

People have been extracting salt here since the Neolithic period, roughly 10,000 BCE. After the earliest settlers, the site was worked in turn by the Iberians, the Romans, and communities through the Middle Ages, with the outcrop exploited as an open surface mine for millennia.

Mining took on an industrial scale at the turn of the 20th century, after engineer Emili Viader i Solé discovered potassium salt deposits within the massif. Between 1900 and 1990, intensive underground extraction transformed the site: at its peak the mine reached over a kilometre in depth and employed 560 workers. Over 65 years of operation, an estimated 37.9 million tons of minerals were extracted from the mountain.

What visitors can see today

The mine closed in 1990, and seven years later, in 1997, the site reopened as the Salt Mountain Cultural Park (El Parc Cultural de la Muntanya de Sal). Visitors today can walk through the former underground mining galleries and see the mountain's striking salt formations up close — translucent walls, crystalline structures, and tunnels shaped by decades of extraction. It's a rare chance to touch rock that, almost everywhere else on Earth, lies buried hundreds of metres below ground.

Frequently asked questions

How far is Cardona from Barcelona? The town sits about 100 km northwest of the Catalan capital, in the Bages region.

Can visitors go inside the mountain? Yes — the former mine site is open to the public through the Salt Mountain Cultural Park, opened in 1997, which offers guided tours of the underground galleries.

Since when has salt been mined here? The earliest evidence of extraction dates back to the Neolithic period, around 10,000 BCE, with the deposit later worked by the Iberians, the Romans, and medieval communities.

Why does the mountain keep growing? Continuous tectonic pressure beneath the surface keeps pushing the salt massif upward, so the outcrop slowly but steadily gains height over time.