The 60th anniversary of the expedition that first took humans to the highest spot on earth – the peak of Everest – was widely celebrated seven years ago. The 60th anniversary of the first expedition to its deepest point has gone almost unnoticed. Yet that trip to the bottom of the Challenger Deep, at the southern end of the Mariana Trench in the Pacific Ocean, was an equally remarkable feat and has rarely been repeated.

While thousands of climbers have since climbed Everest in the footsteps of Tenzing Norgay and Edmund Hillary, only two more people have followed the route of Jacques Piccard and Don Walsh, who reached the bottom in 1960. It was not until 2012 that film-maker James Cameron conducted a solo dive to the almost 11km-deep valley, collecting samples and video. Last year, explorer Victor Vescovo followed suit.

True, other reaches, not quite as distant, have been better explored. But though more than half the world is covered by ocean more than 200m deep – the point at which the sunlight fades and one enters the twilight zone – it was not until 1930 that humans reached the deep sea for the first time. Though scientists have since discovered extraordinary creatures and features, much remains to be discovered.

The reaches of the sea beneath 6km are known as the hadal zone, taking their name from the underworld of the ancient Greeks: the depth of the Mariana Trench ensures it is perpetually dark, and that temperatures are only just above freezing. Yet we are discovering that if it is an inhospitable space for humans, it is far from deserted. Four years ago, a live video feed from a remotely operated vessel allowed ordinary viewers to see the abundant, though “not very diverse”, life to be found down there. The area now enjoys protection, escaping unscathed after it was listed as one of the 27 national monuments that Donald Trump placed under review in 2017.

Other parts of the deep sea are at immediate risk. Even as researchers increase their ability to explore this world, the race is on to exploit it. An analysis published last month in the journal One Earth warned of the threat to the oceans from “blue acceleration”, the recent rise in marine industrialisation, which includes seabed mineral mining.

Greenpeace warned last year that 29 ocean-floor exploration licences had been issued, covering an area totalling 1.3 million sq km – threatening to worsen the climate emergency by disrupting carbon stores in seafloor sediments, as well as destroying barely explored habitats that might offer extraordinary scientific insights – and even new medicines. Though the UN is supposed to wrap up a global ocean treaty this year, many campaigners are pessimistic about the prospect of it offering the kind of protection they believe is needed. Governments must do better. To fall short would not only threaten the habitats and creatures of the deep, but humans too, however unlikely most of us are to ever venture down there.