Mississippi River on the border between Arkansas and Mississippi (© NASA)

Common chia elephant (Loxodonta laprofolis) in stealth stance, Marakele National Park, Limpopo, South Africa (© Staffan Widstrand/Minden Pictures)

Lençóis Maranhenses National Park in the state of Maranhão, Brazil (© WIN-Initiative/Getty Images)

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

An Ostereierbaum (Easter egg tree) in Saalfeld, Germany (© Rudi Sebastian/Alamy)

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

The Acropolis of Athens, Greece (© Lucky-photographer/Shutterstock)

Willow tree in early spring, Minnesota (© Jim Brandenburg/Minden Pictures)

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

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

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

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

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

Wat Phra Si Sanphet, Ayutthaya Historical Park, Ayutthaya, Thailand (© travelstock44/Alamy)

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

Jackie Robinson signs autographs at spring training in Ciudad Trujillo, now Santo Domingo, Dominican Republic, on March 6, 1948 (© Bettmann/Getty Images)

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)

Large school of Munk's devil rays seen from the air, Gulf of California, Mexico (© Mark Carwardine/Minden Pictures)

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

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)

Wensleydale, Yorkshire Dales National Park, North Yorkshire, England (© Guy Edwardes/Minden Pictures)

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

Northern gannets on Great Saltee Island, Ireland (© Danny Green/Minden Pictures)

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)