We have heard a lot about the Grand Canyon in the USA - but not about a similar world under water in the Red Sea until very lately.
The features could be the result of ancient rivers scouring through the rock strata before the Red Sea flooded millennia ago
The British Navy ship made discovery on mission to update Admiralty charts recently.
HMS Enterprise discovered the 250 metre-deep canyon in the Red Sea during a nine-month mission to improve understanding of the waters east of Suez. The 3D images were created after the ship left the Egyptian port of Safaga and were made using the Devonport-based survey ship's multibeam echo sounder.
Commander Derek Rae, commanding officer of HMS Enterprise, said: 'These features could be the result of ancient rivers scouring through the rock strata before the Red Sea flooded millennia ago.
'Some may be far younger and still in the process of being created by underwater currents driven by the winds and tidal streams as they flow through this area of the Red Sea, carving their way through the soft sediment and being diverted by harder bed rock.