River Thames, London, England (© Puthipong Worasaran/Getty Images)

Red-and-green macaws, Mato Grosso do Sul, Brazil (© Ellen Goff/Danita Delimont)

Crystal Lake in the Enchantments, Alpine Lakes Wilderness, Washington (© Mitch Pittman/Tandem Stills + Motion)

Dusky eagle-owls, Pakistan (© zahoor salmi/Getty Images)

Toronto city skyline seen from Lake Ontario, Canada (© Roberto Machado Noa/Getty Images)

Ancient beech tree, Glenariff Forest Park, County Antrim, Northern Ireland (© Dawid K Photography/Shutterstock)

Anna's hummingbird, Santa Cruz, California, USA (© yhelfman/Getty Images)

Abbey of Saint-Martin-du-Canigou, Northern Catalonia, France (© Cyril Gosselin/Getty Images)

Iguazu Falls at the border of Argentina and Brazil (© AirPano LLC/Amazing Aerial Agency)

Vasco da Gama Bridge, Lisbon, Portugal (© Achim Thomae/Getty Images)

Eltz Castle, Germany (© Allard Schager/Alamy)

Dolphin pod near Réunion island, Indian Ocean, overseas department of France (© Joost van Uffelen/Shutterstock)

Point Reyes National Seashore Lighthouse, California, USA (© RMB Images/Photography by Robert Bowman/Getty Images)

Sunrise at Ahu Tongariki, Rapa Nui National Park, Easter Island, Chile (© Piriya Photography/Getty Images)

Varenna on Lake Como, Italy (© Givaga/Getty Images)

Wallabies at sunrise, Adelaide River, Northern Territory, Australia (© Jeremy Woodhouse/Getty Images)

Kerala, India (© Pranavan Shoots/Shutterstock)

Gujō Hachiman Castle, Gifu Prefecture, Japan (© ta2funk ito/500px/Getty Images)

Milky Way over the Elbow River, Alberta, Canada (© Alan Dyer/Getty Images)

Ocracoke Lighthouse on Ocracoke Island, North Carolina, USA (© Chansak Joe/Getty Images)

Oktoberfest in Munich from a high view at sunset (© AllesSuper21/iStock/Getty Images)

Buttermere, Lake District National Park, England, United Kingdom (© Alan Novelli/Alamy Stock Photo)

Waterfall in Skaftafell, Vatnajökull National Park, Iceland (© Nopasorn Kowathanakul/Getty Images)

Giant sequoias, Sequoia National Park, California, USA (© Galyna Andrushko/Shutterstock)

Blue-throated toucanet, Los Quetzales National Park, Costa Rica (© Oscar Dominguez/Tandem Stills + Motion)

Grand Canal and the Basilica di Santa Maria della Salute, Venice, Italy (© Bachir Moukarzel/Amazing Aerial Agency)

Beach at sunrise, Gulf Islands National Seashore, Florida, USA (© Tim Fitzharris/Minden Pictures)

West Cornwall Covered Bridge over the Housatonic River, Connecticut, USA (© pabradyphoto/Getty Images)

Herd of walruses in northern Spitsbergen, Svalbard archipelago, Norway (© AWL Images/DanitaDelimont)