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.

The question of why experienced divers would descend to depths of more than 50 metres using recreational gear — let alone enter a cave while doing so — baffles members of the…

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.