Air Force One casts its shadow over homes as it comes in to land in Allentown, Pennsylania with U.S. President George W. Bush aboard in this October 1, 2004 file photo. (Photo by Jason Reed/Reuters)

A man from the Dominican Republic wears a devil mask while dancing in the street during Carnival celebrations in Panama City, Monday, February 16, 2015. (Photo by Arnulfo Franco/AP Photo)

Visitors look over masses of ice formed around the Canadian “Horseshoe” Falls in Niagara Falls, Ontario, Canada, Thursday, February 19, 2015. (Photo by Aaron Lynett/AP Photo/The Canadian Press)

A migrant carries his belongings as he arrives at the Beijing railway station to catch a train in Beijing, Friday, February 13, 2015. (Photo by Andy Wong/AP Photo)

Musher Michael Ruopp of Germany starts with his sled dogs at the 23rd International Sled Dog Race in Oberhof, central Germany, Sunday, February 24, 2013. (Photo by Jens Meyer/AP Photo)

A woman feeds a pig in her yard during spring flood in the Belarus village of Snyadin near Pripyat river, some 300 km south of Minsk, on April 16, 2013. (Photo by Viktor Drachev/AFP Photo)

People move through a waterlogged street in Gauhati, India, Tuesday, July 16, 2013. Heavy showers flooded some areas in the city on Tuesday. (Photo by Anupam Nath/AP Photo)

A rabbit fails to clear an obstacle during a bunny hop competition at the Old Town Square in Prague, Czech Republic, Monday, April 14, 2014. (Photo by Petr David Josek/AP Photo)