Astronaut Chris Hadfield tweeted this photo of what was the Aral Sea floor from the International Space Station on May 6

Astronaut Chris Hadfield tweeted this photo of the Great Lakes from the International Space Station on May 5.

The metropolitan areas of San Diego, California, and Tijuana, Baja California, together form an international conurbation that crosses the USA-Mexico border

Orthodox believers walk with candles during Easter midnight mass at a church in St.Petersburg, Russia

Elliott Sadler 11, Mike Wallace 1, Justin Allgaier 31, Alex Bowman 99, and Landon Cassill 4 spin through the tri-oval near the end of the NASCAR Nationwide Series auto race

The Wisconsin State Capitol is reflected through a water droplet on a tree in bud on a cold, rainy morning in Madison, Wis

Floyd Mayweather Jr. lands a left jab against Robert Guerrero in the fifth round during a WBC welterweight title fight,

Astronaut Chris Hadfield tweeted this photo of Cape Breton Island, Nova Scotia from the International Space Station

Astronaut Chris Hadfield tweeted this photo from the International Space Station, writing, "A view over central Mexico - just in time for Cinco de Mayo.

Maputo, Mozambique

Romanian orthodox nuns sing in the ossuary at the Pasarea monastery, outside Bucharest, Romania,

In this image made with a specialty lens, horses make their way around turn one during the 139th Kentucky Derby at Churchill Downs