Cave diving is fraught with danger, but the reward is sights like nothing else on Earth | CNN

Cave diving draws explorers to otherworldly underwater mazes that can extend for hundreds of miles and contain species found nowhere else.

The stakes can be high. Veteran cave diver Jill Heinerth says equipment failure or human error can quickly turn an underwater adventure into a deadly event.

Cave systems provide crucial scientific data on Earth's climate history and host species found nowhere else on the planet.

AI-generated summary was reviewed by a CNN editor.

The light fades as divers disappear farther into a cave system, until the greenish hue from their flashlight is all that’s visible, bouncing off walls, picking out creatures humans might never have seen before, and illuminating a world otherwise confined to total darkness.