Submersible dives reveal a startling diversity of life in the depths of the Pacific Ocean — plus, how respiratory infections could awaken dormant cancer cells. This YouTube video cannot be played due to your privacy choices. Please update your preferences here by accepting “Cookies that help with our communications and marketing".

The deep ocean is a world of crushing pressure, freezing temperatures, and eternal darkness. For most of history, scientists considered the deepest parts of our planet — the hadal trenches, plunging more than 6,000 meters (about 20,000 feet) below the surface — to be desolate, life-starved voids. But a recent expedition has shattered that view.