Quinault rainforest, Olympic National Park, Washington state (© Chris Moore/Tandem Stills + Motion)

King penguin father checking egg (© McDonald Wildlife Photography Inc./Getty Images)

Arched iceberg floating off the western Antarctic Peninsula, Southern Ocean (© Steven Kazlowski/Nature Picture Library)

National Museum of African American History and Culture, Washington, DC (© Walter Bibikow/Alamy)

Aerial view of the ruins of Sacsayhuamán, Cusco, Peru (© Creative-Family/Getty Images Plus)

Tremola Road on the Saint Gotthard Pass in Airolo, Switzerland (© Sandro Bisaro/Getty Images)

Hawksbill sea turtle pair near Seven Mile Beach, Grand Cayman, Cayman Islands (© Alex Mustard/Nature Picture Library)

Great Smoky Mountains National Park, Tennessee (© Mint Images/Getty Images)

US flags surrounding the Washington Monument, Washington, DC (© Orhan Cam/Shutterstock)

Sunset in Badlands National Park, South Dakota, USA (© Troy Harrison/Getty Images)