Ty, a 15-year-old boy, poses for a picture while collecting usable items at a landfill dumpsite outside Siem Reap March 19, 2015. Ty, who finished six-grade primary school, said he makes 5 USD per month working at the dumpsite. (Photo by Athit Perawongmetha/Reuters)

Plaster cast moulds of victims of the Mount Vesuvius eruption lie on a display table in a laboratory at Pompeii October 13, 2015. An expert team made up of archaeologists, radiologists, orthodontists and anthropologists began on September 2015 to use CAT scan technology (computerised axial tomography) to peer inside the plaster cast moulds of Pompeii's victims, in a study that has added more detail to previous findings. A 16-layer scan had to be used in order to penetrate the hardened plaster but the results showed up impressive skeletal remains and near perfect teeth. (Photo by Alessandro Bianchi/Reuters)

Street fighting in Berlin between Government troops and Spartacists, during the Spartacist uprising which followed Germany's defeat in World War I. (Photo by Keystone/Getty Images). 1919

In this September 10, 1977, file photo, from left, Hua Guofeng, Chinese Communist Party (CCP) chairman and Mao Zedong's immediate successor; Ye Jianying, CCP vice chairman and future ceremonial head of state; Deng Xiaoping, no formal titles at the time but soon to emerge as paramount leader during the reform era; Li Xiannian, CCP vice chairman and future president; Wang Dongxing, head of the leadership bodyguard unit who helped topple the Gang of Four, view the body of later Chinese leader Mao Zedong in Beijing. (Photo via AP Photo)

A police officer detains a woman on suspicion of collaborating with the 18th street gang during a "Safe House" operation at the Concepcion neighbourhood in San Salvador, July 2, 2015. Salvadoran police make “Safe House” operations at dangerous neighbourhoods of the capital to prevent murders, according to local media. (Photo by Jose Cabezas/Reuters)

A stuntman performs while riding a car inside the “Wall of Death” attraction during a fair in Bhaktapur April 20, 2015. (Photo by Navesh Chitrakar/Reuters)

A sinkhole is seen on the shore of the Dead Sea near Kibbutz Ein Gedi, Israel July 27, 2015. The Dead Sea is shrinking, and as its waters vanish at a rate of more than one meter a year, hundreds of sinkholes, some the size of a basketball court, some two storeys deep, are devouring land where the shoreline once stood. (Photo by Amir Cohen/Reuters)