Residents observe a police officer take up position during an operation at the Mare slums complex in Rio de Janeiro March 25, 2014. The federal troops have taken control of security operations in Mare slums complex to help quell a surge in violent crime following attacks by drug traffickers on police posts in three slums on the north side of the city, government officials said. (Photo by Ricardo Moraes/Reuters)

Hao Han (8), Shaolin kung fu student and child actor. Shaolin Monastery, Henan. (Photo by Mathias Braschler and Monika Fischer)

A high temperature alerts were issued as a record-setting summer heat wave continued to bake most parts of south China. (Reuters)

Three-month old cheetah cubs make their public debut at the Smithsonian National Zoo on July 24, 2012 in Washington, DC. (Photo by T.J. Kirkpatrick)

A baby Chimpanzee plays in its enclosure at Taronga Zoo July 14, 2006 in Sydney, Australia. (Photo by Ian Waldie/Getty Images)

German field telegraph operators at work in Warsaw. (Photo by Hulton Archive/Getty Images). 1st October 1914