White whales and their trainers present a show for visitors at Harbin Pole Aquarium on January 7, 2014 in Harbin, China. Aquarium is one of the tourist highlights of Harbin, attract domestic and foreign tourists visit each year. (Photo by Lintao Zhang/Getty Images)

In this Sunday, April 28, 2013 photograph, people watch as Indian Sailendra Nath Roy attempts to cross Teesta river suspended from a zip wire attached to his ponytail moments before his death in Siliguri, West Bengal state, India. Roy who was named a Guinness World Record holder in 2011 for travelling the farthest distance on a zip wire using hair died during the stunt Sunday when he suffered a heart attack. (Photo by AP Photo)

Robert Galvan, who is on death row for murder, speaks to members of the media at the Adjustment Center yard during a media tour of California's Death Row at San Quentin State Prison in San Quentin, California December 29, 2015. America's most populous state, which has not carried out an execution in a decade, begins 2016 at a pivotal juncture, as legal developments hasten the march toward resuming executions, while opponents seek to end the death penalty at the ballot box. (Photo by Stephen Lam/Reuters)

In this image made available by France's Marine Nationale, the cargo ship TK Bremen sits stranded on a beach near Erdeven, France, on December 16, 2011, spilled fuel oil fouling the water. (AP Photo/Mael Prigent, Marine Nationale)

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)

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)