PlacesWeirdMiners in Mexico found a hidden cave in 2000 with the largest crystals on Earth. The crystals were white gypsum beams up to 37 feet long and 3 feet wide. The heat inside hit 136 degrees with near-total humidity. Without a cooling suit, a person can die within about 10 minutes. In 2015, the mine flooded and sealed the cave shut.5 days ago