Deep below Earth's surface, rock and mineral formations lay hidden with a secret brilliance. Under a black light, the chemicals fossilized within shine in brilliant hues of pink, blue and green.

A Russian expedition, accompanied by two British cave photographers, descended into the depths of one of the world's deepest caves in the remote Gagra Mountains of Abkhazia in the Caucasus.

Deep inside a labyrinthine cave in southwestern France, ancient humans who lived around 30,000 years ago carved horses, ...

Two decades later, I organized a series of expeditions to investigate new deep caves, using dye traces in cave streams to probe Arabika’s potential depth. In 2001 a team led by Ukrainian Yuri ...