At night, the normally placid little white-tip reef sharks turn into voracious hunters.

Lord Norman Tebbit was rather surprised when a large green turtle decided to bite him!

This jolly green giant is typical of the frogfish, that prey even on lionfish at Taba, in the Gulf of Aqaba.

Whale sharks are the largest fish in the sea and this one measured around 18m long. A marine park ranger called The Silver Fox is pictured about to undertake an unbelievable stunt.

The wreck of the SS Liberty lying off the coast of Tulumben in Bali is a favourite overnight roosting place for a hundreds of bumpheaded parrotfish.

This strange-looking dugong seems oblivious to the maddening crowd of swimmers and snorkellers crowding around it at Marsa Abu Dabab on Egypt's Red Sea coast.

Enormous Australian groupers, now regularly hand fed at Ribbon Reef No. 10 on the Great Barrier Reef, were nicknamed Potato Cod by Stan Waterman.

Manta rays are gentle plankton-feeding giants that can be encountered with their accompanying remora fish anywhere in tropical seas.

Dolphins have a couple of reasons for that enigmatic smile.

Divers who go deep now use rebreathers and exotic gas mixes containing helium rather than take a chance using ordinary air to breathe.

The propellers of the former British destroyer HMS Myngs are now covered in vibrantly coloured soft corals.

Fabio Amaral takes a close look at some of the gauges inside the armoured control centre of the World War II aircraft carrier, the USS Saratoga.

Diego Leonardi poses by the enormous multi-bladed prop of the truck-ferry, the Don Pedro, now at rest on the seabed outside Ibiza town.

A modern rebreather diver investigates the 1876 wreckage of the Dunraven, at Beacon Rock, a popular dive site in the Red Sea.

A ‘Jake’ seaplane, sunk at its moorings in Palau during ‘Operation Desecrate One’.

A diver makes a video recording of one of the many World War II British motorbikes that formed part of the cargo of the SS Thistlegorm, a casualty of a German bomber in the Gulf of Suez in 1941.

Bull sharks are implicated in more attacks on people than almost any other species of shark, but here they get hand-fed for the benefit of visiting divers.

Highly poisonous lionfish are beautiful to look at, but they represent a hazard to both divers and endemic species in areas of the world where they are intruders.

A saltwater crocodile is quicker off the mark than a racehorse, can leap out of the water up to its hind legs and is very aggressive. It's not something many want to share the water with.

Getting lost at the surface and not found by the boat crew is one of the most serious hazards a diver can face.

This shark was found by divers trapped in a net. Three experienced divers went back to recover it and made some mistakes in doing so.

Komodo dragons are as big as crocodiles, have a toxic bite and can take down an animal as big as a water buffalo. It's not what you want to meet after finally swimming ashore from being lost at sea.

A shark feed in the Bahamas. The feeder may wear a chainmail suit, but it doesn't absolve them from getting injured.

Caribbean Reef sharks are both impressive and beautiful, but they are timid and don't come close to divers unless there is the chance of a free meal.

In the shark world, size matters and few come bigger than this six-metre-long tiger shark called Scarface in Beqa Lagoon, Fiji.

It was Stuart Cove who originally discovered that a diver could put a shark into ‘Tonic Immobility’ and now shark feeders can demonstrate that all around the world at staged shark feeds.

The three illusive pre-war Fiat cars that are stowed deep in the hold of the Italian liner, the Umbria, scuttled by her crew outside Port Sudan.

Umberto Pelizarri demonstrates to the author his deep breath-hold diving skills. At one time he held the world-record at 150m deep.

Steffi Schwabe, petrologist and underwater explorer, reveals some cave details deep in a flooded Blue Hole in the Bahamas.

A diver carefully cleans off the remains of a two-thousand-year-old amphora found concreted into the seabed at a site near to Egypt's Port Berenice.