Three-toed sloth in Costa Rica (© Harry Collins/Getty Images)

Last light on Half Dome, Yosemite National Park, California, USA (© Adam Burton/Alamy Stock Photo)

Wind River, Brooks Range, Arctic National Wildlife Refuge, Alaska, USA (© Design Pics/DanitaDelimont)

Taj Mahal in Agra, Uttar Pradesh, India (© Tanarch/Getty Images)

Jupiter's icy moon Europa (© NASA/JPL-Caltech/SETI Institute)

African elephants in Tsavo East National Park, Kenya (© Neil Bowman/Minden Pictures)

Cottonwoods through an arch in Coyote Gulch, Glen Canyon Recreation Area, Utah, USA (© Stephen Matera/TANDEM Stills + Motion)

Aerial view of Bora Bora in French Polynesia (© GLF Media/Shutterstock)

Mototi octopus, Lembeh Strait, Indonesia (© Howard Chew/Alamy Stock Photo)

Aspens near Marble, Colorado, USA (© Jason Hatfield/TANDEM Stills + Motion)

Sorano, Tuscany, Italy (© Luigi Vaccarella/eStock Photo)

Cape Breton Highlands, Nova Scotia, Canada (© Cavan Images/Alamy Stock Photo)

Wood duck, Quebec, Canada (© Maxime Riendeau/Getty Images)

Courtyard of the Maidens, Alcázar of Seville, Spain (© Danny Lehman/Getty Images)

Fishing boats at Coco Beach in Goa, India (© Abhinav Sah/Shutterstock)

Great wildebeest migration at Mara River, Kenya (© Ayzenstayn/Getty Images)

Fossils of belemnites and ammonites, Jurassic Coast, Dorset, United Kingdom (© Nature Picture Library/Alamy Stock Photo)

Kochia, Ibaraki Prefecture, Japan (© DigiPub/Getty Images)

Central Park, Manhattan, New York, USA (© mapman/Shutterstock)

Temple of Hathor, Dendera Temple Complex, Qena, Egypt (© Nick Brundle Photography/Getty Images)

Cypress trees in George L. Smith State Park, Georgia, USA (© Chris Moore/TANDEM Stills + Motion)

Palazzo Zuccari, Rome, Italy (© Photon-Photos/Getty Images)

Madame Sherri Forest and the remnant of an old castle, New Hampshire, USA (© yggdrasill/Shutterstock)

Bodie State Historic Park, Mono County, California, USA (© Julien McRoberts/Tetra Images, LLC/Alamy Stock Photo)

Mont Blanc in Chamonix, France (© Simon Schöpf/Getty Images)

Gespensterwald, Nienhagen, Mecklenburg-West Pomerania, Germany (© mauritius images GmbH/Alamy Stock Photo)

Polar bear with cub, Churchill, Manitoba, Canada (© Design Pics/plainpicture)

Pumpkin field, Victoria, British Columbia, Canada (© Shaun Cunningham/Alamy Stock Photo)

Great horned owl (© Mark Newman/Getty Images)

Gran Paradiso National Park, Italy (© Ondrej Prosicky/Alamy)

View of Edinburgh Castle from a churchyard in Scotland, United Kingdom (© Chris Dorney/Alamy Stock Photo)