Ancient theater of Taormina in Sicily, Italy (© Antonino Bartuccio/eStock Photo)

US Army Nurse Corps personnel, 1944 (© Bettmann/Getty Images)

Moonlight and the Milky Way over Mount Rainier in Mount Rainier National Park, Washington (© Brad Goldpaint/Cavan)

Greater one-horned rhinoceroses in Kaziranga National Park, Assam, India (© Robert Harding World Imagery/Shutterstock)

The National Aquatics Center in Beijing, China (© Han Haidan/China News Service via Getty Images)

The island of Mont-Saint-Michel in Normandy, France (© DaLiu/Getty Images)

Great cormorants gliding through a snowstorm in Hesse, Germany (© Wilfried Martin/Getty Images)

Lake Tekapo and Aoraki/Mount Cook National Park on New Zealand's South Island (© Sophie Dover/Getty Images)

The 'Fearless Girl' statue outside the New York Stock Exchange in New York City (© Brendan McDermid/Alamy)

The 'Flower of Life' symbol drawn in the snow by artist Michael Uy, Jacobsdorf, Brandenburg, Germany (© Patrick Pleul/picture alliance via Getty Images)

The Ponte Vecchio, a bridge near Bobbio, Italy (© afinocchiaro/Getty Images)

Field of sunflowers, Ukraine's national flower (© Oleksandrum/Shutterstock)

Girl Scouts camping on the shore of Todd Lake in 1960, Deschutes National Forest, Oregon (© CORBIS/Corbis via Getty Images)

Cable car station at the summit of Zugspitze mountain in Grainau, Garmisch-Partenkirchen, Germany (© Robert Jank/Alamy)

Lanyon Quoit burial chamber, Cornwall, England (© Guy Edwardes/Minden Pictures)

The Roman Forum, Rome, Italy (© Peter Zelei Images/Getty Images)

Giant panda in Wolong National Nature Reserve, Sichuan, China (© Katherine Feng/Minden Pictures)

Coastal redwoods and wood sorrel, Prairie Creek Redwoods State Park, California (© Jack Dykinga/Minden Pictures)

Multicolored powders for sale during Holi (© Nuno Valadas/Getty Images)

Chicagohenge sunset, Chicago, Illinois (© Razvan Sera/Amazing Aerial Agency)

Javan tree frog, Indonesia (© kuritafsheen/Getty Images)

Holy Trinity Church, Stratford-upon-Avon, England (© James Osmond/Getty Images)

Waterfalls in Thousand Springs State Park, Hagerman Valley, Idaho (© knowlesgallery/Getty Images)

Grand Canyon National Park during a thunderstorm, Arizona (© spkeelin/Getty Images)

Red squirrel in a nest of lichen and pine needles, Scottish Highlands (© Neil Anderson/Minden Pictures)

Lauterbrunnen Valley in the Swiss Alps (© Leonid Andronov/Getty Images)

Great tit and yellow crocuses (© Nataba/Getty Images)

Wisteria blooms at Kawachi Fuji Garden in Kitakyushu, Japan (© Steve Tan C K Photography/Getty Images)

Caribbean coast near Parque Nacional Natural Tayrona, Colombia (© Nicholas Hills/Getty Images)

Belted Galloway cows in Scotland (© JohnFScott/Getty Images)

Eiffel Tower in Paris, France (© Susanne Kremer/eStock Photo)