Sunset from Olmsted Point, Yosemite National Park, California, United States (© Robb Hirsch/Tandem Stills + Motion)

Chattooga River in the Appalachian Mountains, North Carolina, United States (© mtilghma/Getty Images)

Toronto City Hall illuminated at night (© EB Adventure Photography/Shutterstock)

Adélie penguins, Antarctica (© Otto Plantema/Minden Pictures)

Danxia landform, Zhangye National Geopark, Gansu, China (© Weiquan Lin/Getty Images)

Moss-covered rocks in Puzzlewood, Forest of Dean, Gloucestershire, England (© Fulcanelli_AOS/Getty Images)

Octopus in defensive posture, Mayotte, Indian Ocean (© Gabriel Barathieu/Minden Pictures)

View of the Sanguinaires Islands from Corsica, France (© Francesco Riccardo Iacomino/Getty Images)

Double-crested cormorants over Monterey Bay, California, United States (© Hiroya Minakuchi/Minden Pictures)

Glade Creek Grist Mill, Babcock State Park, West Virginia, USA (© dszc/Getty Images)

Baker Lake near East Bolton, Quebec (© SEBASTIEN ST-JEAN/Contributor/Getty Images)

Plitvice Lakes National Park, Croatia (© Jan Wlodarczyk/Alamy)

Brown bear in Silver Salmon Creek, Lake Clark National Park and Preserve, Alaska, United States (© Danny Green/Nature Picture Library)

View of the Wroclaw Market Square from the Witches' Bridge in Wroclaw, Poland (© Piotr Mitelski/Shutterstock)

Maligne Lake, Jasper National Park, Alberta (© Andrey Popov/Getty Images)

Life-size replica of Chauvet Cave art in Vallon-Pont-d'Arc, France (© Audrey Poree/Alamy)

Dolbadarn Castle, Llanberis, Eryri National Park (Snowdonia), Wales (© joe daniel price/Getty Images)

Grand Canal in Venice, Italy (© Juan Romero/Cavan Images)

Brown-throated sloth, Puerto Viejo de Talamanca, Costa Rica (© Suzi Eszterhas/Minden Pictures)

Nguyen Hoang Bridge over the Perfume River, Hue, Vietnam (© VU PHAM VAN/Getty Images)

Fall in Naejangsan National Park, South Korea (© Twenty47studio/Getty Images)

Two grey wolves Yellowstone National Park, Wyoming, United States (© John Morrison/Getty Images)

Royal Portuguese Cabinet of Reading, Rio de Janeiro, Brazil (© Antonio Salaverry/Shutterstock)

Mount Sneffels in the San Juan Mountains near Ridgway, Colorado, United States (© lightphoto/Getty Images)