The Naica mine is a famous lead, zinc, and silver mine located in Chihuahua, Mexico. It is known for its stunning crystal formations, particularly the large selenite crystals found in the Cave of the Crystals. These crystals can grow up to 12 meters long and are formed in a unique geological environment. The mine was discovered in the 18th century, but its remarkable crystal caves were found in 2000. The extreme conditions, including high temperatures and humidity, make it challenging for humans to explore. The Naica mine remains a significant site for both mining and scientific research.