'Legacy' mural painted by Josh Sarantitis and Eric Okdeh within the Mural Arts Program in Philadelphia, Pennsylvania (© Vespasian/Alamy)

The 369th Infantry returns to New York City, 1919 (© Science History Images/Alamy)

Alpine marmot in Hohe Tauern National Park, Austria (© Misja Smits/Minden Pictures)

Corjuem Fort in Goa, India (© Ingvar Kuznetsov/Shutterstock)

Big Air Shougang venue in Shijingshan District, Beijing, China (© Gao Zehong/VCG via Getty Images)

Monarch butterflies in the Monarch Butterfly Biosphere Reserve, Angangueo, Mexico (© Sylvain Cordier/Minden Pictures)

Winter in Oymyakon, Russia (© Alexandr Berdicevschi/Getty Images)

Rideau Canal Skateway during Winterlude in Ottawa, Canada (© Preappy/Getty Images)

Rock art near Santa Fe, New Mexico (© Scott Warren/Cavan)

The Ceremony Hall of Icehotel in Jukkasjarvi, Sweden (© Wolfgang Kaehler/LightRocket via Getty Images)

The Old City of Bern, Switzerland (© Xantana/Getty Images)

'Go' by Kehinde Wiley, displayed inside Moynihan Train Hall at New York City's Penn Station (© Spencer Platt/Getty Images)

Darwin's Arch with Darwin Island in background, Galápagos, Ecuador (© miralex/Getty Images)

American bison in Yellowstone National Park, Wyoming (© Gerald Corsi/Getty Images)

Heart-shaped island with sandy beach, offshore coral reef, Indian Ocean, Maldives (© Willyam Bradberry/Shutterstock)

Red lanterns hanging on trees during the Lantern Festival in Chengdu, Sichuan, China (© Philippe Lejeanvre/Getty Images)

Beech woodland in hoarfrost, Cranborne Chase, Dorset, England (© Guy Edwardes/Minden Pictures)

Flamenco dancers outside Palma de Majorca, Spain (© Torleif Svensson/Getty Images)

Great tits on a branch during winter in France (© Eric Ferry/Alamy)

Mount Logan in Kluane National Park and Reserve, Yukon, Canada (© plainpicture/Design Pics/Robert Postma)

Humpback whales and dolphins, Hawaii (© drewsulockcreations/Getty Images)

The Washington Monument seen from the Lincoln Memorial in Washington, DC (© lucky-photographer/Getty Images)

Two Bactrian camels in Kazakhstan for Twosday (© Nurlan Kulcha/Alamy)

The cypress tunnel at Point Reyes National Seashore in California (© Spondylolithesis/Getty Images)

Flowing river inside a glacier cave, Vatnajökull, Iceland (© Marco Bottigelli/Getty Images)

Lamplugh Glacier in Glacier Bay National Park, Alaska (© Andrew Peacock/Getty Images)

Polar bear mother with cubs in Wapusk National Park, Manitoba, Canada (© Andre Gilden/Minden Pictures)

Hoarfrost and snow in the Cotswolds, England (© Peter Adams/Getty Images)