A window cleaner passes a lighter to his colleague while rappelling from a new building in Tianjin March 23, 2007. (Photo by Reuters/Stringer)

A woman crosses an open sewer as she makes her way to her house in a Christian slum in Islamabad December 4, 2014. (Photo by Zohra Bensemra/Reuters)

In this December 18, 2013 photo released by Six Flags Discovery Kingdom, 32 men dressed as Santa Claus ride the 150-foot tall SkyScreamer tower swing ride at Six Flags Discovery Kingdom in Vallejo, Calif. (Photo by Jason Quintos/AP Photo/Six Flags Discovery Kingdom)

People watch dragon dance performance in front of a business establishment in celebration of Chinese New Year at Manila's Chinatown district of Binondo, Philippines, Friday, January 31, 2014. (Photo by Bullit Marquez/AP Photo)

A newborn baby giraffe shows its tongue at the Planckendael zoo in Mechelen, 25 kilometers North of Brussels, Tuesday, February 18, 2014. The calf was born on Valentines day, February 14, and has a heart shaped spot on the hip. (Photo by Yves Logghe/AP Photo)

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)

Passengers from the ferry sinking off South Korea's southern coast are rescued by the South Korean Coast guard in the water off the southern coast near Jindo, south of Seoul, on April 16, 2014. Almost 300 people were missing after a ferry sank off South Korea on Wednesday, the coastguard said, in what could be the country's biggest peacetime disaster in nearly 20 years. (Photo by AP Photo)

Golden gate Bridge Fog Thick early morning fog engulfed a huge world famous bridge so that only the very tip of it is visible above the clouds. Photographer Ali Erturk, 33, hiked to the spot at 4am to capture the stunning sight of the Golden Gates bridge immersed in the dense swirls of fog. (Photo by Solent News and Photo Agency)