Castelbouc and the Gorges du Tarn along the Tarn River in France (© Stefan Schurr/Westend61/Offset)

Die Festung Guaita in San Marino (© Piercarlo Abate/Shutterstock)

Guaita Tower in San Marino (© Piercarlo Abate/Shutterstock)

Tegallalang terrace farms in Ubud, Bali, Indonesia (© gorgeoussab/Shutterstock)

Castillo San Felipe del Morro in Old San Juan, Puerto Rico (© grandriver/Getty Images)

Mount Fanjing, the highest peak of the Wuling Mountains, in southwest China (© Keitma/Alamy)

Southern yellow-billed hornbills in Kruger National Park, South Africa (© Ben Cranke/Getty Image)

Central Coast vineyards in Arroyo Grande, California (© Ian Shive/Tandem Motion + Stills)

Gerenuk in Tsavo National Parks, Kenya (© Byrdyak/iStock/Getty Images Plus)

The Tower of Voices at the Flight 93 National Memorial in Shanksville, Pennsylvania (© Amy Cicconi/Alamy)

The Milky Way seen from Canyonlands National Park in Utah (© Cavan Images/Offset)

Walrosse bei Kvitøya, Spitzbergen, Norwegen (© Ole Jorgen Liodden/Minden Pictures)

Walruses near Kvitøya in the Svalbard archipelago, Norway (© Ole Jorgen Liodden/Minden Pictures)

Wachsenburg Castle, Drei Gleichen, Thuringia, Germany (© Raimund Linke/Masterfile)

Detail of a portobello mushroom (© Justin Galloway/Offset)

Detail of the Statue of Liberty, on Liberty Island, New York (© Judy Dillon/Getty Images Plus)

The Villarrica volcano in Chile on September 2, 2018 (© Cristobal Saavedra Escobar/Reuters)

A common loon in the Superior National Forest in Minnesota (© Jim Brandenburg/Minden Pictures)

Quaking aspens of Pando in Fishlake National Forest, Utah (© Don Paulson/Danita Delimont)

'The Wall for Peace' and the Eiffel Tower in Paris for the International Day of Peace (© Prisma by Dukas Presseagentur GmbH/Alamy)

Fireworks during La Mercè Festival in Barcelona, Spain (© Lucas Vallecillos/age fotostock)

Equinox at the Temple of Kukulcan in Chichen Itza, Mexico (© Somatuscani/Getty Images Plus)

A mountain gorilla eating in a tree in the Bwindi Impenetrable National Park, Uganda (© Robert Haasmann/Minden Pictures)

Arctic surfing in the Lofoten Islands, Norway, for the Lofoten Masters (© Nicolás Pina/Tandem Stills + Motion)

｢夜明けの琵琶湖大橋｣ 滋賀県 (© Hiroshi Kusumoto/EyeEm/Getty Images)

The Nankoweap Granaries of the Grand Canyon in Arizona (© Jack Dykinga/Minden Pictures)

Hocking Hills State Park in Ohio for National Public Lands Day (© Sara Winter/Getty Images Plus)

Autumnal landscape near the town of Clavijo in Spain's Rioja wine region (© Olimpio Fantuz/eStock Photo)

An aerial view of Beijing Daxing International Airport, China (© Xinhua/Alamy)