With individual crystals spanning nearly 40 feet, caves of giant Selenite crystals formed over 500,000 years, resting on a fault line over a magma chamber underneath Chihuahua, Mexico. During that time, the caves were submerged in mineral rich water in which the selenite crystals slowly grew. The largest cave was discovered and drained by miners in 2000. In 2017, the caves re-flooded. In the seventeen intervening years, scientists captured these images and conducted fascinating mineralogical, crystallographic, biogeochemical, and microbial studies.