04-20Mute swan chicks shelter under mom's tail feathers, Massapequa Preserve, Long Island, New York - Vicki Jauron/Getty Images)
04-16Aerial view of Grand Prismatic Spring, Yellowstone National Park, Wyoming - AirPano LLC/Amazing Aerial Agency)
04-12Waning gibbous moon above the Earth's horizon, photographed from the International Space Station - NASA)