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

Exploring deep, dangerous underwater cave systems offers scientists and divers unparalleled glimpses into Earth’s history, even though the margins for error are tragically slim.

​ Exploring deep, dangerous underwater cave systems offers scientists and divers unparalleled glimpses into Earth’s history, even though the margins for error are tragically slim. Read More Breaking News, Latest News and Videos | CNN