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 on a single tank of air — let alone enter a cave while doing so — baffles members of the relatively close-knit deep-sea diving community.

A FORMER military diver has claimed that “rules were broken” in the high-risk cave dive that killed five Italians – as the desperate search for bodies enters its fourth day.

The group had been diving in ⁠caves in the Vaavu Atoll at a depth ⁠of around 50m (165ft). They were reported missing by the crew of a vessel they were travelling on when they failed to resurface.

Five Italian divers and a rescuer have died in the Maldives. What caused the deaths?

Australia's peak cave diving body has finalised its investigation into the death of a man underground in a South Australian cave system. Victorian man Gary Gibson, 65, died while diving in Tank Cave at Tantanoola, in the state's South East on November 29.

Cave diving is a highly technical and dangerous activity that requires specialized training, equipment and strict safety protocols.