Grizzly bear cub siblings playing in Denali National Park, Alaska (© Ron Niebrugge/Alamy)

Lençóis Maranhenses National Park in Barreirinhas, Brazil (© WIN-Initiative/Getty Images)

Lighthouse at Cape Aniva, Sakhalin Island, Russia (© Amazing Aerial Agency/Offset by Shutterstock)

Lighthouse at Cape Aniva, Sakhalin, Russia (© Amazing Aerial Agency/Offset by Shutterstock)

Saut du Brot stone bridge in the Areuse Gorge, Neuchâtel, Switzerland (© Andreas Gerth/eStock Photo)

The Parthenon temple in the Acropolis of Athens, Greece (© Lucky-photographer/Shutterstock)

Amboli Waterfalls in Maharashtra, India (© ePhotocorp/iStock/Getty Images Plus)

Black grouse male calling at lek site in Kuusamo, Finland (© Oliver Smart/Alamy)

Square Tower Group in Hovenweep National Monument, Utah (© Brad McGinley Photography/Getty Images)

Mount Yoshino, Nara Prefecture, Japan (© Sean Pavone/iStock/Getty Images Plus)

Earth from the International Space Station, photographed by astronaut Jeff Williams (© Jeff Williams/NASA)

Sunset at Golden Temple in Amritsar, India (© szefei/shutterstock)

Wildflowers in the Carrizo Plain National Monument, California (© Dennis Frates/Alamy)

Wat Phra Si Sanphet, Ayutthaya Historical Park, UNESCO World Heritage Site, Ayutthaya, Thailand (© travelstock44/Alamy)

Dalí Theatre-Museum in Figueres, Spain (© Valerija Polakovska/Shutterstock)

New River Gorge Bridge in the New River Gorge National Park and Preserve, West Virginia (© Entropy Workshop/iStock/Getty Images Plus)

Montalbano Elicona, Messina, Sicily, Italy (© Antonino Bartuccio/SOPA Collection/Offset by Shutterstock)

Montalbano Elicona, Messina, Sicily, Italy (© Antonino Bartuccio/SOPA Collection/Offset by Shutterstock)

Tegalalang Rice Terraces, Ubud, Bali, Indonesia (© Michele Falzone/Alamy)

Ancient ruins of Hazara Rama Temple in Hampi, Karnataka (© Dmytro Gilitukha/shutterstock)

The north coast of Madeira, Portugal (© Hemis/Alamy)

Casa Batlló in Barcelona, Catalonia, Spain (© Marco Arduino/Sime/eStock Photo)

The Cholla Cactus Garden in Joshua Tree National Park, California (© Bryan Jolley/Tandem Stills + Motion)

Adélie penguins diving off an iceberg in Antarctica (© Mike Hill/Getty Images)

Great Hornbill spotted in West Bengal, India (© Debapratim Saha/Minden Pictures)

Yayoi Kusama's 'Pumpkin' artwork on Naoshima Island, Japan, in August 2018 (© WireStock/Alamy)

Yayoi Kusama's 'Pumpkin' artwork on Naoshima Island, Japan, in August 2018 (© WireStock/Alamy)

Aerial view of tidal channels in marshland of the Mockhorn Island State Wildlife Management Area, Virginia (© Shane Gross/Minden Pictures)

'The Spirit of Harlem' mural by Louis Delsarte in Harlem, New York City (© Pietro Scozzari/agefotostock)

Thoseghar Waterfalls in Maharashtra, India (© Sonali Kumar/iStock/Getty Images Plus)