The biggest challenge early divers and engineers faced in building and living inside these structures was understanding the effect of breathing pressurised gas for long periods of time. Experiments designed to work out the effects of living in hyperbaric chambers, in which the air can be compressed to mimic conditions at depth, began in the 1930s.

A few years after Cousteau proved that people could live underwater inside a chamber for a month at a time, the US Navy built its experimental habitat Sealab I off the coast of Bermuda, 192ft (56m) underwater. Since then, there have been a handful of other underwater labs including the Tektite habitat and Hydrolab, but Aquarius is the only one still running for scientific researchers. Burkepile is one of the few who have worked there.

While the science and technology has certainly improved, there are a lot of things that haven’t changed much since the days of Cousteau’s Conshelf program. Underwater habitats are still very cramped, and the environment is harsh.

Aquarius has only about 400 sq ft (37 sq m) of space inside, but it feels even smaller when you’re sharing it with five other people and a whole laboratory’s worth of equipment (take a tour of Aquarius in the video below). “I tell people it’s the size of a school bus, but that’s actually probably too big because inside there are tables and scientific equipment,” says Burkepile.