Quiver trees under the Milky Way, Keetmanshoop, Namibia (© Wim van den Heever/naturepl.com)

Aerial view of the Colosseum, Rome, Italy (© Nico De Pasquale Photography/Getty Images)

Marine Corps War Memorial, Arlington, Virginia (© f11photo/Shutterstock)

Black-tailed prairie dogs at Roberts Prairie Dog Town, Badlands National Park, South Dakota (© Greg Vaughn/Getty Images)

Interstellar clouds in the Lagoon Nebula, captured by the Hubble Space Telescope (© ESA/NASA)

Sea stacks of Bandon Beach in Bandon, Oregon (© Grant Ordelheide/TANDEM Stills + Motion)

Polar bear in Churchill, Manitoba, Canada (© karen crewe/Getty Images)

Colorful lanterns at the temple of Wat Phra That Hariphunchai, Lamphun, Thailand (© MR. ANUJAK JAIMOOK/Getty Images)

Peña Roya beech forest, Moncayo Natural Park, Zaragoza, Aragon, Spain (© David Santiago Garcia/DEEPOL by plainpicture)

Tower Bridge, London, England (© Nick Brundle Photography/Getty Images)