Jordi Chias / Woman snorkeller swimming inside lagoon Toau atoll, Tuamotu Archipelago, French Polynesia, Pacific Ocean.

Christophe Courteau / African elephants (Loxodonta africana) swimming across Chobe River, trunks raised above surface for breathing, Chobe National Park, border between Botswana and Namibia.

David Pattyn / Children snorkelling in the sea and swimming with bottlenose dolphins (Tursiops truncatus) with boat approaching. Indian Ocean, Zanzibar, Tanzania, August 2014.

Angelo Gandolfi / Snorkeller with shoal of Piraputanga (Brycon hilarii), Rio Olha d'Agua at Cabeceira do Prata, Bonito, Mato Grosso do Sul, Brazil

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...

Franco Banfi / Two women snorkeling in front of the cave, Raja Ampat, Irian Jaya, West Papua, Indonesia, Pacific Ocean. Model released.

Juergen Freund / Coral reef split level with mangroves with snorkeller, Raja Ampat, West Papua, Indonesia, February 2012 Model released.

Franco Banfi / Free diver with Blue shark (Prionace glauca) Pico Island, Azores, Portugal, Atlantic Ocean, July. No release available.

Michele Westmorland / Snorkeler swimming with harmless Jellyfish (Mastigias papua etpisonii), Jellyfish Lake, Rock Islands, Palau, Micronesia.

Todd Mintz / Scad fish / Horse mackerel (Trachurus trachurus) shoal with young male snorkeller, Bonaire, Dutch Caribbean. Model released.

Jeff Rotman / Child snorkeling and exploring on coral reef wall. Red Sea, Egypt. Model released Model released.

Doug Perrine / Researcher Guy Stevens photographs belly spot identification pattern of Reef manta ray (Manta alfredi formerly Manta birostris) feeding on plankton, Hanifaru Bay, Baa Atoll, Maldives, Indian Ocean, Oc...