Inaki Relanzon / Hawksbill turtle (Eretmochelys imbricata) swimming underwater, Nosy Be, North Madagascar.

Vincent Grafhorst / Minden / River in sandstone cave, Sof Omar Cave, Ethiopia

Vincent Grafhorst / Minden / Crater of active volcano at twilight, Erta Ale, Danakil Depression, Ethiopia

Pascal Kobeh / A school of Bluespotted cornetfish (Fistularia commersonii), Red Sea, Egypt.

Shane Gross / Dugong (Dugong dugon) feeding on Tapegrass (Halophila stipulacea), accompanied by juvenile Golden trevally fish (Gnathanodon speciosus). Marsa Alam, Egypt.

Shane Gross / Dugong (Dugong dugon) male and juvenile Golden trevally (Gnathanodon speciosus) shoal swimming over Turtlegrass (Halophila stipulacea) seagrass bed. Marsa Alam, Egypt.

Karine Aigner / A white cat peeks out a blue door. Chefchaouen, Morocco.

Brandon Cole / Crocodile fish (Cymbacephalus beauforti) camouflaged, Egypt, Red Sea.

Brandon Cole / Masked butterflyfish (Chaetodon semilarvatus) Egypt, Red Sea.

Brandon Cole / Bluespotted ribbontail ray (Taeniura lymma) Egypt, Red Sea.

Brandon Cole / Oceanic whitetip shark (Carcharhinus longimanus), view from above as it swims away. Egypt, Red Sea.

Brandon Cole / Oceanic whitetip shark (Carcharhinus longimanus) and Pilotfish (Naucrates ductor) swimming under a stormy surface. Egypt, Red Sea.

Brandon Cole / Giant moray eel (Gymnothorax javanicus), peering up from inside colony of Plate Fire Coral (Millepora platyphylla). Egypt, Red Sea.

Brandon Cole / Steel pompano (Trachinotus stilbe) fish swimming under stormy seas at Roca Redonda offshore Baja, Mexico, Pacific Ocean.

Alex Mustard / Dugong (Dugong dugon) male, swims over seagrass meadow (Halophila stipulacea) accompanied by a young Golden trevally (Gnathanodon speciosus). Marsa Nabaa, Marsa Alam, Egypt. Red Sea

Alex Mustard / Dugong (Dugong dugon) male feeding on a seagrass meadow (Halophila stipulacea), accompanied by a young Golden trevally (Gnathanodon speciosus). Marsa Nabaa, Marsa Alam, Egypt. Red Sea

Alex Mustard / Dugong (Dugong dugon) male feeding on a seagrass meadow (Halophila stipulacea), accompanied by a young Golden trevally (Gnathanodon speciosus). Marsa Nabaa, Marsa Alam, Egypt. Red Sea

Alex Mustard / Oceanic whitetip shark (Carcharhinus longimanus) is framed by the surface. Elphinstone reef, Marsa Alam, Egypt. Red Sea.

Alex Mustard / RF - Pod of Spinner dolphins (Stenella longirostris) cruise in formation over the sand of a lagoon while sleeping. Egypt. Red Sea (This image may be licensed either as rights managed or royalty free.)

Alex Mustard / Hard corals (including Acropora sp., Platygyra sp. and Pocillopora spp.) growing in shallow water and reflected in the surface. Ras Umm Sid, Sharm El Sheikh, Sinai, Egypt. Red Sea

Alex Mustard / Dugong (Dugong dugon) male and juvenile Golden trevally (Gnathanodon speciosus) swimming over Seagrass (Halophila stipulacea) meadow. Marsa Nabaa, Marsa Alam, Egypt.

Alex Mustard / Green turtle (Chelonia mydas) feeding on Seagrass (Halophila stipulacea), blowing sand out of nostrils, on sea floor. Marsa El Shouna, Marsa Alam, Egypt.

Alex Mustard / Green turtle (Chelonia mydas) resting on sea floor and two juvenile Golden trevally (Gnathanodon speciosus). Marsa El Shouna, Marsa Alam, Egypt.

Alex Mustard / Spinner dolphin (Stenella longirostris) pod socialising close to surface. Fury Shoal, Sataya Reef, Marsa Alam, Egypt.

Alex Mustard / Oceanic whitetip shark (Carcharhinus longimanus) swimming close to surface. Brothers Islands, Egypt.

Alex Mustard / Forster's hawkfish (Paracirrhites forsteri) on a coral reef. Jackson Reef, Tiran, Sinai, Egypt. Strait of Tiran, Gulf of Aqaba, Egypt.

Alex Mustard / Tiger cardinalfish (Cheilodipterus macrodon) male mouth brooding a clutch of eggs behind his sharp teeth. Gubal Island, Egypt. Strait Of Gubal, Red Sea.

Alex Mustard / Yellowtail tang (Zebrasoma xanthurum) male courting a female prior to spawning at dusk on a coral reef. Temple, Ras Umm Sid, Sharm El Sheikh, Sinai, Egypt. Red Sea.

Alex Mustard / Striped mackerel (Rastrelliger kanagurta) shoal swimming with open mouths, filtering for zooplankton. Marsa Shouna, Port Ghalib, Marsa Alam, Egypt. Red Sea

Jeff Rotman / Head and gills of juvenile Scalloped hammerhead shark (Sphyrna Lewini), Kane'ohe Bay, Hawaii, Pacific Ocean.

Jordi Chias / Wave breaking over the reef, Table coral (Acropora) Safaga, Egypt, Red Sea.

Jordi Chias / Hawksbill turtle (Eretmochelys imbricata) Port El Ghalib, Egypt, Red Sea.

Jordi Chias / Red Sea anemonefish (Amphiprion bicinctus) in their home, a Sea anemone (Heteractis magnifica), on a coral reef. Big Brother island, Red Sea. Egypt.

Eric Baccega / Mountain gorilla (Gorilla beringei beringei) juvenile female stretching hand out towards camera, member of the Kabirizi group, Virunga National Park, North Kivu, Democratic Republic of Congo, Africa,...

Alex Mustard / Striped mackerel (Rastrelliger kanagurta) mouth wide open as it swims through the water, filtering zoopankton with its gill rakers. Marsa Shouna, Port Ghalib, Marsa Alam, Egypt. Red Sea

Luis Quinta / Beach at the north of Principe Island, Democratic Republic of Sao Tome and Principe, Gulf of Guinea.

David Pattyn / Common brown lemur (Eulemur fulvus) jumping amongst branches, Anjajavy Private Reserve, north west Madagascar.

David Pattyn / Common brown lemur (Eulemur fulvus) portrait, Anjajavy Private Reserve, north west Madagascar.

Alex Mustard / Hawksbill turtle (Eretmochelys imbricata) male chomps on soft coral. Jackson Reef, Sinai, Egypt. Strait of Tiran, Red Sea.

Alex Mustard / Whitetip shark (Carcharhinus longimanus) head on beneath the surface. Rocky Island, Egypt. Red Sea

Christophe Courteau / Steam rising from the crater of Nyiragongo Volcano. Virunga National Park, North Kivu Province, Democratic Republic of Congo. September 2015.

Christophe Courteau / Lava Lake at night in the crater of Nyiragongo Volcano, Virunga National Park, North Kivu Province, Democratic Republic of Congo. September 2015.

Christophe Courteau / Lava Lake at night in the crater of Nyiragongo Volcano, Virunga National Park, North Kivu Province, Democratic Republic of Congo. September 2015.

Roland Seitre / Dromedary camel (Camelus dromedarius) calf Oriental Great Erg sand dunes, Jbil National Park, Tunisia.

Jabruson / Mozambican children with captive Yellow Baboon youngster (Papio cynocephalus) young animal caught during troop crop raiding. Pemba to Montepuez highway, north-eastern Mozambique, November 2011. Specia...

Alex Mustard / Reef octopus (Octopus cyanea) portrait near wreck. Gubal Island, Egypt. Red Sea.