Tuskegee Airmen reading a map

Bluebell flowers carpet the Hallerbos forest floor, Flanders, Belgium

Sundial on Parnidis Dune, Curonian Spit, Lithuania

Aerial view of the City of Adelaide shipwreck with trees growing on it, Magnetic Island, Queensland, Australia

Mount Etna erupting in 2013, Sicily, Italy

Inisheer, the smallest of the three Aran Islands, in Galway Bay, Ireland

Giant panda cub at Bifengxia Panda Base, Sichuan, China

Screech owl resting in a tree cavity, Massapequa Preserve, Long Island, New York

Astronomical clock, Lyon, France

Common rhododendrons in Semper Forest Park, Rügen, Germany

A balloon flies over the Pyramid of the Sun at sunrise in Teotihuacan, Mexico

Thor's Well at Cape Perpetua on the Oregon coast