Only one-third of the Caves of Nerja in Andalusia, Spain can be visited, but the Plymouth Caving Club went on an expedition to enter previously unexplored passages in the cavern and captured some unbelievable photos.

“We had to take a grueling two-and-a-half hour hike with a lot of gear to reach a new cave called Chupadora in which I pushed some new previously unexplored passage,” caver Josh Bratchley from Gunnislake, England told Caters News Agency.

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The group reached the depths of 1,066 feet on their exploration, spending 11 hours at a time underground exploring new areas. According to Bratchley, it was remarkable the photos turned out as well as they did.

“The cameras used for these pictures were ones that had an LCD failure and some pictures were taken blind so it is great that the pictures came out so well,” said Bratchley.

The Caves of Nerja in Andalusia are a total of two-and-a-half miles long, but according to the Institute of Tourism in Spain, only the Low Galleries can be visited. The area is visitor-friendly due to its height and width.

The Upper Gallery and Show Gallery are home to many prehistoric cave paintings, but tourist access to that portion of the cave is limited to special tours.

The collection of images above were taken from the Plymouth University Caving Club’s expedition to unknown parts of the Caves of Nerja.