Participants wearing masks during a hazy day at the Beijing International Marathon in front of Tiananmen Square, in Beijing, October 19, 2014. (Photo by Reuters/Stringer)

White lioness Azira lies in the cage with her three white cubs, on February 4, 2014. Zoo owner Andrzej Pabich says white lions often have defects that prevent giving birth, or the mother rejects her cubs, but Azira has been patiently feeding and caring for her little ones. (Photo by Czarek Sokolowski/Associated Press)

Injured horses huddle together in Oklahoma City on Monday. (Photo by Chris Landsberger/The Oklahoman)

This handout photograph released by Taipei City Zoo on July 11, 2013 shows a newly-born panda cub of giant panda Yuan Yuan in an incubator at Taipei Zoo in Taipei. The public will have to wait three months to catch a glimpse of the first panda born in Taiwan, officials said after she was successfully delivered by parents who were gifted from China. (Photo by AFP Photo/Taipei City Zoo)

The provincial highest chimney collapses as it is demolished by explosives in Shenyang, Liaoning province, April 28, 2014. The 150-metre-high chimney used to be part of a local heating factory, according to local media. (Photo by Sheng Li/Reuters)

A tourist poses for a picture with the Sphinx at the Pyramids of Giza in Cairo, Egypt, on October 19, 2011. (Reuters/Jamal Saidi)

Participants wear traditional clogs as shepherds lead their sheep through the center of Madrid, October 28, 2012. (Photo by Andres Kudacki/Associated Press)

Winner of the Sandow bodybuilding competition, Mr. Murray. (Photo by Reinhold Thiele/Thiele/Getty Images). Circa 1905