Houseboats in Alappuzha, Kerala, India (© Martin Harvey/The Image Bank/Getty Images)

Porcini mushroom (© vnosokin/Getty Images)

Porto Flavia, Sardinia, Italy (© Visualframing/Adobe Stock)

Bisti/De-Na-Zin Wilderness, New Mexico, USA (© Ian Shive/Tandem Stills + Motion)

Anna's hummingbird (© Dee/Getty Images)

Grand Canal, Venice, Italy (© Alexander Duffner/Alamy)

Howgill Fells, Yorkshire Dales National Park, England (© davidnmoorhouse/iStock/Getty Images Plus)

Humpback whales, Massachusetts, USA (© Eric Kulin/plainpicture)

Riou island, Calanques National Park, France (© Jason Langley/AWL Images/Offset by Shutterstock)

San Juan Islands, Washington state, USA (© Stephen Matera/Tandem Stills + Motion)

River Avon, Bath, England (© Robert Harding World Imagery/Offset by Shutterstock)

Hainich National Park, Thuringia, Germany (© mauritius images GmbH/Alamy)

Tombstone Territorial Park, Yukon, Canada (© Ron Erwin/All Canada Photos/Alamy)

Venice Skatepark, Venice Beach, Los Angeles, USA (© Ingus Kruklitis/Getty Images)

Aldeyjarfoss waterfall, Highlands of Iceland (© Jim Patterson/Tandem Stills + Motion)

Birnbeck Pier, Bristol Channel, Weston-super-Mare, England (© Stephen Davies/Adobe Stock)

Benagil Cave, Algarve, Portugal (© Michael Malorny/Offset by Shutterstock)

Roe deer buck, Schleswig-Holstein, Germany (© Helge Schulz/Minden Pictures)

Land's End, Cornwall, England (© Andrew Turner/Getty Images)

Starlings during the autumn migration (© Viking/Alamy)

Willow trees, Lake Bret, Bugey, France (© Jean-Philippe Delobelle/Minden Pictures)

Baby white rhinoceros and mother, Hluhluwe–Imfolozi Park, South Africa (© Martin Harvey/Alamy)

Neptune (© NASA/JPL)

Cusco Cathedral, Plaza de Armas, Cusco, Peru (© sharptoyou/Shutterstock)

Escarpment Trail, Porcupine Mountains Wilderness State Park, Michigan, USA (© Pat & Chuck Blackley/Alamy)

Mackenzie River, Canada, and Beaufort Sea (© Norman Kuring, GSFC/NASA/USGS Landsat)

Thorn bug, Pico Bonito National Park, Honduras (© Mac Stone/Tandem Stills + Motion)

The Broads National Park, Thurne, Norfolk, England (© Steven Docwra/Getty Images)

Wood bison, Northwest Territories, Canada (© Don Johnston/agefotostock)

Container ship, San Pedro, California, USA (© Cameron Venti/Getty Images)