Doug Perrine / Giant squirrelfish (Sargocentron spiniferum) at cleaning station in the cockpit of wreck of Panorama Air Tour Beech H18S that crashed in 1983 after take-off from Keahole airport, Kona, Hawaii.

Ernie Janes / Boat full of people watching Common Seals (Phoca vitulina) on sand bank at Blakeney Point, Norfolk, August 2013.

David Pattyn / Mountains in snow, Aiguille du Tour with Tower Glacier in front, Chamonix, Haute Savoie, France. December 2011

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

Roland Seitre / American Crocodile (Crocodylus acutus) seen on 'The Crocodile Man Tour'. Carara National Park, Tarcoles, Costa Rica, August 2008.

Peter Cairns / 2020VISION / Group of tourists wearing waterproof clothing and life jackets photograph seabirds from zodiac boat on tour around Bass Rock, North Berwick, Firth of Forth, Lothian, Scotland, UK, August 2011

Peter Cairns / 2020VISION / Group of tourists wearing waterproof clothing and life jackets photograph Gannet colony from zodiac boat on tour around Bass Rock, North Berwick, Firth of Forth, Lothian, Scotland, UK, August 2011. Di...

Peter Cairns / 2020VISION / Group of tourists wearing waterproof clothing and life jackets in zodiac boat for seabird safari tour around Bass Rock, North Berwick, Firth of Forth, Lothian, Scotland, UK, August 2011

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

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

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