Espen Bergersen / Humpback whales (Megaptera novaeangliae) showing tail fluke when they dive. Kvanangen, Troms, Norway. December

David Fleetham / Humpback Whale (Megaptera novaeangliae) beginning a deep dive. Hawaii.

Neil Aldridge / Pied kingfisher (Ceryle rudis) erupts from the water after an unsuccessful dive into the Chobe River, Chobe National Park, Botswana.

Franco Banfi / Devilrays (Mobula tarapacana) two viewed from below, Ambrosio dive site, Santa Maria Island, Azores, Portugal, Atlantic Ocean.

Franco Banfi / Devilray (Mobula tarapacana) swimming near the surface with remoras, Ambrosio dive site, Santa Maria Island, Azores, Portugal, Atlantic Ocean

Franco Banfi / Devilrays (Mobula tarapacana) large group at the surface, Ambrosio dive site, Santa Maria Island, Azores, Portugal, Atlantic Ocean

Franco Banfi / Cory's shearwaters (Calonectris diomedea) diving among a mass of shoaling fish to feed, along with Atlantic spotted dolphins (Stenella frontalis), Formigas Islet dive site, Azores, Portugal, Atlantic...

Franco Banfi / Cory's shearwaters (Calonectris diomedea) diving among a mass of shoaling fish to feed, along with Atlantic spotted dolphins (Stenella frontalis), Formigas Islet dive site, Azores, Portugal, Atlantic...

Franco Banfi / Scuba diver with Devilray (Mobula tarapacana), Ambrosio dive site, Santa Maria Island, Azores, Portugal, Atlantic Ocean

Chris & Monique Fallows / King penguin (Aptenodytes patagonicus) group on ice preparing to dive. South Georgia Island.

Michael Pitts / British Admiralty anchor - mid 1750's - possibly from the wreck of HMS Colossus - wrecked 1798. St Mary's Roads. Isles of Scilly. England, UK, August 2013.

Chris & Monique Fallows / Gentoo penguins (Pygoscelis papua) diving into the ocean, Antarctic peninsula, Antarctica.

Chris & Monique Fallows / African penguins (Spheniscus demersus) hunting underwater, False Bay, Cape Town, South Africa.

Chris & Monique Fallows / African penguins (Spheniscus demersus) diving underwater, False Bay, Cape Town, South Africa.

Alex Mustard / A fisherman swims down to touch the statue of Christ Of The Abyss (Cristo degli abissi) for good fortune, in the Marine Protected Area of Portofino (Area Marina Protetta, Portofino), Liguria, Italy. M...

Alex Mustard,Alex Mustard / Divers explore mediaeval mill building, now flooded in Capodacqua lake. Gran Sasso National Park, Abruzzo, Italy.

Michael Pitts,Michael Pitts / Engine room ventilator shafts of oil tanker 'Seiko Maru'. Sunk in Chuuk Lagoon 17/18th February 1944, Chuuk Lagoon, Pacific

Michael Pitts,Michael Pitts / Divers on the wreck of the tugboat, 'Tienstin'. Abu Galawa, Red Sea, July 2010

Michael Pitts,Michael Pitts / Wreck of Aichi E13A, Japanese World War Two float plane, sunk by American fighters, Solomon Islands.

Michael Pitts / Diver on the wreck of the US Submarine tender USS Macaw, sunk in the World War II due to a navigation error, Midway atoll, Pacific Ocean. Model released.

Sue Daly,Sue Daly / Jewel Anemones (Corynactis haddoni) colonising the wreck of HMNZS Canterbury, Bay of Islands, New Zealand, February 2013

Franco Banfi / Scuba diver under ice next to large ice formation, Arctic circle Dive Center, White Sea, Karelia, northern Russia, March 2010. No release available.

Franco Banfi / Beluga whale (Delphinapterus leucas) swimming under ice, Arctic circle Dive Center, White Sea, Karelia, northern Russia. Captive

Franco Banfi / Scuba diver under ice, surfacing to the hole, viewed from underneath, Arctic circle Dive Center, White Sea, Karelia, northern Russia March 2010. No release available.

Franco Banfi / Scuba diver under ice and ice formation, Arctic circle Dive Center, White Sea, Karelia, northern Russia March 2010. No release available.

Franco Banfi / Beluga whale (Delphinapterus leucas) swimming under ice and exhaling air, with scuba diver in background, Arctic circle Dive Center, White Sea, Karelia, northern Russia, captive

Franco Banfi / Person well dressed for cold temperatures, Arctic circle Dive Center, White Sea, Karelia, northern Russia. No release available.

Franco Banfi / Scuba diver with special head hood for cold water diving, Arctic circle Dive Center, White Sea, Karelia, Northern Russia, April 2009. No release available.

Todd Mintz / Iceberg dive, diver next to ice floe, Pond Inlet, Baffin Island, Nunavut, Canada, June

Chadden Hunter / Emperor penguins (Aptenodytes forsteri) males dive through openings in the sea ice to take their first swim in over 4 months as they have spent the bleak winter incubating their eggs. Cape Washington,...

Andrew Parkinson / 2020VISION / Adult Coot (Fulica atra) running on the surface of a lake, Derbyshire, England, UK, March 2010. Did you know? Coots can dive up to 2 metres.

Andrew Parkinson / Red kite (Milvus milvus) in swooping dive, Gigrin Farm, Mid Wales, UK, March.

Juergen Freund / Crinoids or featherstars covering a coral bommie with dive boat looming overhead, West New Britain, Papua New Guinea

Juergen Freund / Split level of dive boat "Seven Seas", coral reef and island, Komodo NP, Indonesia, August 2009.

Juergen Freund / Swim-through at dive site called Boo with colourful corals in the foreground. Misool, Raja Ampat, West Papua, Indonesia

Juergen Freund / Light streaming into a shallow cave in a dive site called The Passage, with a diver swimming up towards the foliage visible above. North Raja Ampat, West Papua, Indonesia, February 2010. Model release...

Juergen Freund / Member of West Papuan dive boat crew free-swimming underwater. North Raja Ampat, West Papua, Indonesia, February 2010

Martin Camm / Carwardine / Illustration of Common bottle-nosed / Bottlenose dolphin (Tursiops truncatus) and Indo-Pacific dolphin (T. aduncus) breach and dive sequence in profile (Wildlife Art Company).

Mark Carwardine / Humpback whale (Megaptera novaeangliae) fluking - lifting the tail in the air before a dive, Sea of Cortez, Baja California, Mexico

Jeff Rotman / Caribbean Reef shark (Carcharhinus perezi) in hypnotic trance being lifted by shark handler, Bahamas, Caribbean Sea. Model released.

Jeff Rotman / Shark handler wearing chain mail suit feeding Caribbean Reef shark (Carcharhinus perezi) Bahamas, Caribbean Sea. Model release Model released.

Jeff Rotman / Shark handler wearing chain mail suit holding Caribbean reef shark (Carcharhinus perezi) in hypnotic trance. Caribbean sea Model released.

Jeff Rotman / Shark expert Neal Watson fighting off a Lemon shark (Negaprion brevirostris) with a shark club, The Bahamas, Caribbean. (model released) Model released.

Jeff Rotman / Free diver coming up from dive to explore coral reef, Sinai, Egypt, Red Sea Model released Model released.

Mark Brownlow / Rebreather instructor Ian Thomas and cameraman Didier Noirot prepare to dive under the ice, Lake Baikal, world's deepest and oldest (and largest by volume) freshwater lake, Siberia, Russia. BBC Plane...

TOM MANGELSEN / Peregrine falcon diving, Arctic. Peregrines are the fastest animals in the air, recorded at 200mph in a dive!

Norbert Wu / Emperor Penguin (Aptenodytes forsteri) group swimming quickly with bubble trail, can dive to 600 meters and stay down for 20 minutes, Antarctica

Norbert Wu / Swordfish (Xiphias gladius) worldwide, can tolerate temperatures of five degrees Celsius and dive to 650 meters, uses sword to kill prey such as squid, can grow to 14 feet and 1200 pounds, Sardinia, I...

Norbert Wu / Emperor Penguin (Aptenodytes forsteri) group swimming, can dive to 600 meters and stay down for 20 minutes, Antarctica

Flip Nicklin / Southern Right Whale (Eubalaena australis) researchers Roger Payne, right, Jim Darling, left, and Gustavo Alvarez Colombo, center, watching individual dive, Peninsula Valdez, Argentina

Fred Bavendam / Diver exploring the Liberty shipwreck, Bali's most popular dive site, Tulamben, Bali, Indonesia

Mark Payne-Gill / Peregrine falcon in flight {Falco peregrinus} Captive, England, UK. Peregrines have been recorded at speeds of 217mph in an attack dive - more than nine times the maximum speed of a human (27mph). Per...

Doug Perrine / Sperm whale mother and calf {Physester macrocephalus} North Atlantic, NB peeling skin from rubbing against other whales. Sperm whales can dive to a depth of 3,000m and hold their breath for 2 hours! H...

Doug Allan / Weddell seal swims under ice {Leptonychotes weddelli} Antarctica. Weddell seals can dive to a depth of 700m!

Alex Mustard / Split level photograph of a liveaboard dive boat (M.Y. Whirlwind), anchored near a coral reef, at sunet. Ras Katy, Sharm El Sheikh, Sinai, Egypt. Red Sea

Tony Wu / Bryde's whale (Balaenoptera brydei) commencing dive. Sri Lanka.

Michel Roggo / Dive camp of Swiss-Russian dive team on frozen Lake Baikal. Near shore, aerial shot. Photographed for The Freshwater Project extended. Near Khuzhir, Olchon Island, Irkutsk Oblast and Buryat Republic,...

Michel Roggo / Dive camp of Swiss-Russian dive team on frozen Lake Baikal. Near shore, aerial shot. Photographed for The Freshwater Project extended. Near Khuzhir, Olchon Island, Irkutsk Oblast and Buryat Republic,...

Michel Roggo / Dive camp of Swiss-Russian dive team on frozen Lake Baikal. Near shore, aerial shot. Photographed for The Freshwater Project extended. Near Khuzhir, Olchon Island, Irkutsk Oblast and Buryat Republic,...

Doug Perrine / Shimmering heat waves distort the image of diver as he samples erupting pillow lava at ocean entry of Kilauea Volcano, Hawaii Island.

Doug Perrine / Videographer filming pillow lava erupting underwater at Kilauea Volcano, Hawaii.

Doug Perrine / Diver shaping erupting pillow lava by hand to form underwater lava sculptures at ocean entry from Kilauea Volcano, Hawaii.

Doug Perrine / Diver sampling red hot pillow lava at underwater eruption of Kilauea Volcano, Hawaii.

Shane Gross / Philippine dive guide looking at Crown-of-thorns sea star (Acanthaster planci) Malapascua, Philippines.

Espen Bergersen / Humpback whales (Megaptera novaeangliae) showing the humpback when they dive. Kvanangen, Troms, Norway. December

Mark Carwardine / Humpback whale (Megaptera novaeangliae) tail fluke above water about to dive with whale watching boat behind, Bay of Fundy, New Brunswick, Canada

Franco Banfi / Scouting the river on a small boat driven by an electric motor ready to dive, Formoso River, Bonito, Mato Grosso do Sul, Brazil

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

Tui De Roy / Blue-footed booby (Sula nebouxii), five flying, folding wings to dive into water. Cape Douglas, Fernandina Island, Galapagos.

Tui De Roy / Blue-footed booby (Sula nebouxii), four beginning dive towards sea. Espumilla Beach, Santiago Island, Galapagos.

Alex Mustard / Diver cleaning plastic from a dive site in Lembeh. The group of divers collected three large sacks (much bigger than the small collecting bag pictured) from an area about the size of two tennis courts...

Magnus Lundgren / Wild Wonders of China / A dive boat in Sai Kung archipelago, Hong Kong, China. June, 2016.

Magnus Lundgren / Wild Wonders of China / Woman from Ocean Park Conservation Foundation Hong Kong, in charge of the seahorse survey, demonstrating seahorse tagging before dive, Hong Kong, China. June, 2016.

Ashley Cooper / The RAF Red Arrows flying over the Lake District during the Windermere Air Show, England, UK. July.

Linda Pitkin / Dive boats moored at beach, Triton Bay, near Kaimana, West Papua, Indonesia, March 2017

David Fleetham / Eleven year old PADI certified junior scuba diver, Sean Fleetham and schooling Bluestripe snapper (Lutjanus kasmira) off Second Cathedral, and dive site off the island of Lanai, Hawaii. December 2013....

David Fleetham / Bugis schooner, live-aboard dive vessel, at anchor in a limestone island lagoon, Uranie Island, Raja Ampat, West Papua, Indonesia.

David Fleetham / Divers step off a dive boat into the Pacific Ocean out from Ukumehame, Maui, Hawaii. March 2014. Model released.

David Fleetham / Fijian dive guide feeding Grey reef shark (Carcharhinus amblyrhynchos) off Mana Island, Fiji.

David Fleetham / Panoramic view of live-aboard dive vessel at anchor in a limestone island lagoon, Uranie Island, Raja Ampat, West Papua, Indonesia.

David Fleetham / Dive vessel "Solmar V" off Guadalupe Island, Mexico, Eastern Pacific Ocean.

Alex Mustard / Remora (Remora remora) schooling beneath dive boat on a coral reef. North Male Atoll, Maldives. Indian Ocean.

Lynn M. Stone / Eastern brown pelican (Pelecanus occidentalis carolensis) sub-adult in dive, Tampa Bay, St. Petersburg, Florida, USA.

Franco Banfi / Sperm whale (Physeter macrocephalus) fluke above water as it starts to dive, Dominica, Caribbean Sea, Atlantic Ocean, Vulnerable species.

Franco Banfi / Sperm whale (Physeter macrocephalus) tail as it starts to dive, Dominica, Caribbean Sea, Atlantic Ocean, Vulnerable species.

Franco Banfi / Sperm whale (Physeter macrocephalus) fluke above water as it starts to dive with a whale's watching boat loaded with tourists watching, Dominica, Caribbean Sea, Atlantic Ocean, Vulnerable species.

Franco Banfi / Sperm whale (Physeter macrocephalus) fluke above water as it starts to dive, Dominica, Caribbean Sea, Atlantic Ocean, Vulnerable species.

Lynn M. Stone / Common loon (Gavida immer) with sleepy chick on its back, initiating a dive during which it will leave chick unattended, New Hampshire, USA. Non-ex.

Michel Roggo / Dive guide in spring in Lake Baikal, Lake Baikal UNESCO World Heritage Site, Siberia, Russia. May 2015. Photographed for The Freshwater Project.

Michel Roggo / Dive boat in front of a fishing village on the shore of Lake Malawi, Malawi, November 2015. Photographed for The Freshwater Project.

Franco Banfi / Reef covered with soft coral,( Dendronephthya sp) and Black coral, (Antipathes sp) with shoal of Jewel fairy basslet (Pseudanthias squamipinnis) South Point dive site, Sanganeb reef, Sudan, Red Sea

Franco Banfi / Soft coral (Dendronephthya sp) with shoal of Jewel fairy basslet, (Pseudanthias squamipinnis) South Point dive site, Sanganeb reef, Sudan, Red Sea

Franco Banfi / Shoal of Blackfin barracuda (Sphyraena qenie) South Point dive site, Sanganeb reef, Sudan, Red Sea

Franco Banfi / Reef and shoal of Jewel fairy basslet (Pseudanthias squamipinnis) South Point dive site, Sanganeb reef, Sudan, Red Sea

Franco Banfi / Scuba diver and soft coral (Dendronephthya sp) South Point dive site, Sanganeb reef, Sudan, Red Sea