Koala in a eucalyptus tree, Great Otway National Park, Australia (© Jamie Lamb - elusive-images.co.uk/Getty Images)

Rainbow houses in the town of Houten, Netherlands (© George Pachantouris/Getty Images)

Town of Pienza in Tuscany, Italy (© zpagistock/Getty Images)

Red maple in fall, Canada (© LiuSol/Getty Images)

Least chipmunk, Kootenai National Forest, Montana, United States (© Donald M. Jones/Minden Pictures)

Chittorgarh Fort, Rajasthan, India (© chetansoni/Shutterstock)

Devils Tower National Monument, Wyoming, United States (© Laura Hedien/Getty Images)

Keel-billed toucan in Costa Rica (© Juan Carlos Vindas/Getty Images)

Aspen trees during fall, Fishlake National Forest, Utah, United States (© Danita Delimont/Getty Images)

Sea otters, Prince William Sound, Alaska, United States (© Gerald Corsi/Getty Images)

Swing carousel at Oktoberfest, Munich, Bavaria, Germany (© LOOK-foto/Alamy)

Thousand Islands region, St. Lawrence River, USA-Canada border (© benedek/Getty Images)

Serpentine stairs of Dunquin Pier, County Kerry, Ireland (© Hugh O'Connor/Getty Images)

A young bull moose in Denali National Park, Alaska, United States (© Grant Ordelheide/TANDEM Stills + Motion)

A nighttime view of the Gulf Coast states from 362 kilometres above Earth (© Stocktrek Images/Getty Images)

Coastline at Cape Breton Highlands National Park, Nova Scotia (© Tiago_Fernandez/Getty Images)

A waterfall in Olympic National Park, Washington, United States (© Chris Moore/TANDEM Stills + Motion)

Chimney Rock, Point Reyes National Seashore, California, United States (© Enrique Aguirre Aves/Getty Images)

Spinner dolphin pod in the Red Sea, Marsa Alam, Egypt (© Franco Banfi/Nature Picture Library)

View from Salto del Gitano, Monfragüe National Park, Cáceres, Extremadura, Spain (© Daniel Viñé Garcia/Getty Images)

Hay bales, North Yorkshire, England (© Nick Brundle Photography/Getty Images)

A female Eurasian red squirrel carrying moss, Switzerland (© Jean-Luc and Francoise Ziegler/Minden Pictures)

Library@orchard, Singapore (© Darwin Fan/Getty Images)

Gdańsk on the banks of the Motława river, Poland (© Oscar Dominguez/TANDEM Stills + Motion)

Rufous hummingbird, Golden Gate Park, San Francisco, California, United States (© jeremyborkat/Getty Images)

Pacific Park, Santa Monica State Beach, California, United States (© EXTREME-PHOTOGRAPHER/Getty Images)

CN Tower illuminated at night in Toronto, Ontario (© R.M. Nunes/Shutterstock)

Grizzly bears wrestling, Katmai National Park and Preserve, Alaska, United States (© Cavan Images/Adobe Stock)

Camel thorn trees, Deadvlei, Namib-Naukluft Park, Namibia (© Inge Johnsson/Alamy Stock Photo)

Calcite Springs Overlook and Yellowstone River, Yellowstone National Park, Wyoming (© Rebecca L. Latson/Getty Images)