Naica Caves
The Naica caves are lead, zinc and silver mines located in the state of Chihuahua in Northern Mexico. They are also home to the largest selenite crystals in the world.
The lead mines were discovered in 1828, which led to the foundation of the Naica settlement, the natural crystal caves were discovered by accident in 1910 and 2000, the mines were closed in 2015 due to constant flooding.
Visits to the cave were extremely restricted and dangerous, the underground temperature of 58C-136F and more than 90% humidity made it impossible to stay inside for more than 10 mins without oxygen supply and special suits.
Air-cooled plastic tents were created inside the caves to allow two-hour missions.
The Cave of Crystals, lined with limestone floors, walls and ceilings is filled with gypsum crystals that are almost 40 feet long and 3 feet wide, weighting around 50 metric tons each.
It was created roughly 26 million years ago, when flowed magma created a mountain which housed mineral rich waters with calcium sulfate in its caverns, this created the perfect conditions for the crystals to grow.
The Cave of Swords is another cave within, that has walls covered in 6 feet crystals. These crystals took approximately 1 million years to grow, according to scientists “This is equivalent to adding the thickness of a sheet of paper every 200 years”.
Although they are magnificent, the exploitation of mines in the state by the monopolization of the territory in the 60’s by Grupo Peñoles (the second largest Mexican mining company), led to the exploitation and displacement of indigenous and poor communities in the area and left without work to many residents when ending operations.