Alex Mustard / 2020VISION / Common sunstar (Crossaster papposus), brittlestars and sealoch anemones form a typical undersea community in a Scottish sea loch, Loch Duich, Ross and Cromarty, Scotland, UK, April 2011

Juergen Freund / Scientists on the Undersea Explorer research vessel testing a coconut rattle to attract sharks. Queensland, Australia. John Rumney.

Tui De Roy / Galapagos Sea Lion (Zalophus wollebaeki) pup cavorting in undersea cave, Seymour Island, Galapagos Islands, Ecuador

David Fleetham / Painted frogfish (Antennarius pictus) with first dorsal spine and lure extended to attract prey. Dumaguete, Philippines.

Michael Pitts / Diver examining the sandstone structure of the Yonaguni undersea monument, Yonaguni, East China Sea, Japan. February 2014.

Michael Pitts / Diver examining the sandstone structure of the Yonaguni undersea monument, Yonaguni, East China Sea, Japan. February 2014.

Michael Pitts / Diver examining the sandstone structure of the Yonaguni undersea monument, Yonaguni, East China Sea, Japan. February 2014.

Philip Stephen / Dive support vessel "Normand Pioneer" undertaking subsea operations on the North Sea, September 2009.

Juergen Freund / 13 captured Chambered nautilus {Nautilus pompilius} in an ice box on board 'Undersea Explorer'. They will be measured, recorded and released in the reef. 2007

Juergen Freund / Guests help out 'Undersea Explorer' marine biologist Qamar to engrave, photograph and measure caught Nautilus for research, Queensland, Australia, 2007

Juergen Freund / Guests help out 'Undersea Explorer' marine biologist Qamar to engrave, photograph and measure caught Nautilus for research, Queensland, Australia, 2007

Juergen Freund / Shell of a caught Chambered nautilus {Nautilus pompilius} being engraved with a number for research onboard the 'Undersea Explorer', Queensland, Australia, 2007