Martin Willis / Mangroves along coast and boat, Deluge Inlet, Hinchinbrook Island National Park, Queensland, Australia

Gary Bell/ Oceanwide / Surfer, Solitary Islands Marine Park, New South Wales, Australia

Jeff Foott / Hiker near waterfall and rainbow, Nevada Fall, Yosemite National Park, California

Suzi Eszterhas / African Elephant (Loxodonta africana) in defensive posture towards safari vehicle, Sabi Sands Private Game Reserve, South Africa

Yva Momatiuk & John Eastcott / Ice climber scaling Skaftafellsjokull Glacier, Skaftafell National Park, Iceland

Yva Momatiuk & John Eastcott / Ice climbers atop Skaftafellsjokull Glacier, Skaftafell National Park, Iceland

Yva Momatiuk & John Eastcott / Ice climber scaling Skaftafellsjokull Glacier, Skaftafell National Park, Iceland

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

Colin Monteath/ Hedgehog House / Kayakers paddling back to cruise ship Polar Pioneer, Lemaire Channel, Antarctic Peninsula, Antarctica

Pascal Tordeux / Aerial view of Cappadocia with hot air balloon, Turkey, March 2006.

Pete Oxford / Yellow-tailed Surgeonfish (Prionurus laticlavius) school and snorkeler, Galapagos Islands, Ecuador

Pete Oxford / Yellow-tailed Surgeonfish (Prionurus laticlavius) school and snorkelers, Galapagos Islands, Ecuador

Pete Oxford / Red-footed Booby (Sula sula) flying juvenile being photographed by tourist, Genovesa Island, Galapagos Islands, Ecuador

Pete Oxford / Galapagos Sea Lion (Zalophus wollebaeki) pup and tourist, Galapagos Islands, Ecuador

Pete Oxford / Pacific Green Sea Turtle (Chelonia mydas agassizi) and snorkeler, Galapagos Islands, Ecuador

Pete Oxford / Marine Iguana (Amblyrhynchus cristatus) group photographed by tourist, Fernandina Island, Galapagos Islands, Ecuador

Thomas Marent / African Elephant (Loxodonta africana) crossing dirt road near tourists, Serengeti National Park, Tanzania

David Noton / Hot air balloon over the Temples of Bagan at dawn, Myanmar, November 2012.

Christophe Courteau / Tourists and guide using snowshoes on an ecotourism trekking holiday, Svalbard, Norway, June, 2012. Model released.

Staffan Widstrand / Kayaking past icebergs in Svalbard, Norway, July 2011. Model released.

Juan Carlos Munoz / People descending into the Thrihnukagigur volcano a dormant volcano, now used for tours, Iceland, Europe, June 2012

Colin Monteath / Campers read in tents lit by flashlight, Cascade Saddle, Mount Aspiring National Park, New Zealand

Pete Oxford / Dugout canoe in blackwater stream, Yasuni National Park Biosphere Reserve, Amazon rainforest, Ecuador

Colin Monteath / Mt Sefton, climber at dawn above Mueller hut and cloud-filled Mueller Glacier, Mt Cook National Park, New Zealand

Flip Nicklin / Whale Shark (Rhincodon typus) surrounded by several scuba divers, threatened, Cocos Island, Costa Rica

Flip Nicklin / Two scuba divers swimming through sea cave with schooling Grunts, Cocos Island, Costa Rica

Gerry Ellis / Dromedary (Camelus dromedarius) trio with Bedouins at sunset, Oasis Dakhia, Great Sand Sea, Sahara Desert, Egypt

Gerry Ellis / African Lion (Panthera leo) kill surrounded by tourists, Tanzania border, Kenya

Konrad Wothe / Flight safari, Okavango Delta, Botswana

Konrad Wothe / Safari airplane flying over the flooded Okavango Delta, Botswana

Tui De Roy / Glacier with tourist expedition in inflatable zodiac, southern Greenland Fjords, Greenland

Colin Monteath / Cerro Torre and Fitzroy reflected in small pond at dawn, Loma Plieque Tumbado, Los Glaciares National Park, Patagonia, Argentina

Colin Monteath / Hiker, Cerro Torre and Fitzroy reflected in small pond at dawn, Loma Plieque Tumbado, Los Glaciares National Park, Patagonia, Argentina

Colin Monteath / Mountaineer enjoying the view of Mt Everest and the Himalayan Mountains at sunset from Gokyo Ri, Khumbu, Nepal

Yva Momatiuk & John Eastcott / Lone hiker walking along the base of a sandstone butte strong pattern of wavy lines in petrified sand dunes are exposed by erosion, Vermilion Cliffs National Monument, Colorado Plateau, Utah

Yva Momatiuk & John Eastcott / Lone hiker walking on colorful sandstone strong pattern of wavy lines in petrified sand dunes are exposed by erosion, Vermilion Cliffs National Monument, Colorado Plateau, Utah

Yva Momatiuk & John Eastcott / Alaska Range in spring snow, photographer resting in valley below mountains, Denali National Park and Preserve, Alaska

Gerry Ellis / Mosquito Cove at dusk, Antigua, Caribbean

Gerry Ellis / Hurricane Bay, Virgin Islands National Park, Saint John Island, Virgin Islands, Caribbean

Colin Monteath / Humpback Whale (Megaptera novaeangliae) observed by tourists in a zodiac boat near Melchoir Island, Antarctic Peninsula, Antarctica

Colin Monteath / Climber enjoying view of Mt CookÆs Caroline Face from Ball Pass, Mt Cook National Park, New Zealand

Michael & Patricia Fogden / Brilliant trail with hiker, Monteverde Cloud Forest Reserve, Costa Rica

Tim Fitzharris / Tourists viewing Grand Prismatic Pool, Midway Geyser Basin, Yellowstone National Park, Wyoming

Gerry Ellis / Sandstone blocks of White Pyramid of King Snefru at Dakshur, Egypt

Gerry Ellis / The pyramids of Giza in evening light, Giza, Egypt

Colin Monteath / Climber on the summit of Pik Kommunizma at 7,500 meters elevation, highest mountain in the Pamirs, a mountain range in Tajikistan, central Asia

Konrad Wothe / Tourists on Russian icebreaker breaking through pack ice, Antarctica

Konrad Wothe / Ice climber on Perito Moreno Glacier, Los Glaciares National Park, Argentina

Claus Meyer / Visitors explore an expansive cavern with stalactites, Vale Do Peruacu, Minas Gerais, south Cerrado savannah, Brazil

Konrad Wothe / Gray Whale (Eschrichtius robustus) breaching while tourists watch, Mexico

Konrad Wothe / Cardon (Pachycereus pringlei) cactus photographed by tourist, largest cacti in the world and may live over 200 years, Sonoran Desert, Baja California, Mexico

Matthias Breiter / Two climbers at Ruth Glacier, with Mt McKinley towering above them, Denali National Park and Preserve, Alaska

Norbert Wu / Scuba diver among colorful corals

Norbert Wu / Sipadan Island, a rich oceanic island surrounded by coral reef, Borneo

Jim Brandenburg / Canoe bow with autumn trees, Discovery Lake, Superior National Forest, Minnesota

Jim Brandenburg / Inuits dog sledding in midnight sun, Ellesmere Island, Nunavut, Canada

Norbert Wu / Atlantic Spotted Dolphin (Stenella frontalis) swimming with Katherine Gilman, Little Bahama Bank, Caribbean

Flip Nicklin / Orca (Orcinus orca) leaping, watched by tourists from Stubbs Island charter boat, Johnstone Strait, northeast Vancouver Island, Canada

Flip Nicklin / Humpback Whale (Megaptera novaeangliae) tails and sailboat with whale watching tour, Hawaii

Flip Nicklin / Manta Ray (Manta birostris) Flower Garden Banks National Marine Sanctuary, Louisiana, Gulf of Mexico

Mitsuaki Iwago / Cruise ship in storm, Antarctica

Tui De Roy / Galapagos Sea Lion (Zalophus wollebaeki) checking out tourist, Mosquera Island, Galapagos Islands, Ecuador

Michio Hoshino / Illuminated tent beneath snow-covered mountains and Aurora borealis, Alaska

Norbert Wu / Atlantic Spotted Dolphin (Stenella frontalis) playing with Poppi Gilman, Little Bahama Bank, Caribbean

Flip Nicklin / Gray Whale (Eschrichtius robustus) touched by tourists, San Ignacio Lagoon, Baja California, Mexico

Tui De Roy / Tourists cruising Beagle Channel beneath Romanche Glacier, Patagonia, Chile

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

Norbert Wu / Snorkeler Deanna Mah at The Baths, British Virgin Islands

Flip Nicklin / Atlantic Spotted Dolphin (Stenella frontalis) pod with female snorkeler, Bahamas

Fred Bavendam / Butterfly Perch (Caesioperca lepidoptera) and diver swimming amidst Gorgonian Sea Whips, Fans and various kinds of Sponges at 40 meters depth, Tasman Peninsula, Tasmania, Australia

Fred Bavendam / Marine Iguana (Amblyrhynchus cristatus) group photographed by tourist, Santiago Island, Galapagos Islands, Ecuador

Flip Nicklin / Bottlenose Dolphin (Tursiops truncatus) interacting with a female tourist, Dolphin Quest Learning Center, Hawaii

Asgeir Helgestad / Climber on Mt Galdhopiggen, 2468 metres, Jotunheimen NP, highest point in Norway

Chase Dekker / Humpback Whale (Megaptera novaeangliae) gulp feeding on Northern Anchovy (Engraulis mordax) near whale watching boat, Monterey Bay, California

Chase Dekker / Humpback Whale (Megaptera novaeangliae) pod gulp feeding on Northern Anchovy (Engraulis mordax) near tourists, Monterey Bay, California

Chase Dekker / Cheetah (Acinonyx jubatus) male and tourists, Masai Mara, Kenya

Juergen & Christine Sohns / African Elephant (Loxodonta africana) on road near safari vehicles, Addo National Park, South Africa

Martin Willis / Boat near sand island, Sudbury Cay, Great Barrier Reef, Queensland, Australia

Martin Willis / Boat near sand island, Beaver Cay, Great Barrier Reef, Queensland, Australia

Ralph Pace / Tourists and calving glacier, South Sawyer Glacier, Alaska

Stefan Christmann / Interior of Antarctic Logistics Centre International aeroplane at Novolazarevskaya Station, Atka Bay, Queen Maud Land, Antarctica. November 2017.

Stefan Christmann / Antarctic Logistics Centre International aeroplane Novolazarevskaya Station, Atka Bay, Queen Maud Land, Antarctica. November 2017.

Stefan Christmann / Antarctic Logistics Centre International aeroplane Novolazarevskaya Station, Atka Bay, Queen Maud Land, Antarctica. November 2017.

Stefan Christmann / Antarctic Logistics Centre International aeroplane Novolazarevskaya Station, Atka Bay, Queen Maud Land, Antarctica. November 2017.

Stefan Christmann / Antarctic Logistics Centre International aeroplane Novolazarevskaya Station, Atka Bay, Queen Maud Land, Antarctica. November 2017.

Stefan Christmann / Antarctic Logistics Centre International aeroplane Novolazarevskaya Station, Atka Bay, Queen Maud Land, Antarctica. November 2017.

Ralph Pace / Bottlenose Dolphin (Tursiops truncatus) and diver, Revillagigedo Islands, Mexico

Cyril Ruoso / Ring-tailed Lemur (Lemur catta) trio with tourists, Anja Park, Madagascar

Jeff Foott / Large number of tourists on overcrowded hiking trail, Delicate Arch, Arches National Park, Utah

Jeff Foott / Kayakers and eroded lakeshore, Apostle Islands National Lakeshore, Lake Superior, Wisconsin

Chase Dekker / Blue Whale (Balaenoptera musculus) pair and whale watching boat, Monterey Bay, California

Chase Dekker / Hiker near waterfall and basalt columns, Svartifoss Waterfall, Skaftafell National Park, Iceland

Chase Dekker / Hikers near glacial lake, Moraine Lake, Banff National Park, Alberta, Canada

Chase Dekker / Sea Otter (Enhydra lutris) group and kayakers, Moss Landing, California

Chase Dekker / Hiker at waterfall, Kirkjufellsfoss, Snaefellsnes Peninsula, Iceland

Chase Dekker / Bus driving down road towards Mount Denali, Denali National Park, Alaska