A demonstrator catches fire after the gas tank of a police motorbike exploded during clashes in a protest against Venezuelan President Nicolas Maduro, in Caracas on May 3, 2017. Venezuela' s angry opposition rallied Wednesday vowing huge street protests against President Nicolas Maduro' s plan to rewrite the constitution and accusing him of dodging elections to cling to power despite deadly unrest. (Photo by Juan Barreto/AFP Photo)

Devotees wear costumes made of banana leaves as they head to church to attend mass as part of a religious festival, in honor of St. John the Baptist, also known locally as the “mud people” festival, in Aliaga town, Nueva Ecija province, north of Manila, on June 24, 2017. Farmers coated in mud paraded in Philippine villages on June 24 to mark one of the Catholic nation's most colourful religious festivals. (Photo by Noel Celis/AFP Photo)

A herd of elephants cross a road that passes through the flooded Kaziranga National Park in the northeastern state of Assam, India, July 12, 2017. (Photo by Anuwar Hazarika/Reuters)

Three Chinese soldiers at the time of a civil war in China. (Photo by General Photographic Agency/Getty Images). 1922

A man covered with thermal blanket walks along railway tracks beside an improvised refugee camp on the border line between Macedonia and Serbia near the northern Macedonian village of Tabanovce, Thursday, March 10, 2016. Around 1.500 migrants and refugees are stranded at Tabanovce transit center for refugees in northern Macedonia. (Photo by Boris Grdanoski/AP Photo)

A pair of tigers soak in a shallow pool at Tiger Temple, a Buddhist monastery where paying visitors can interact with young adult tigers, in Kanchanaburi, Thailand, March 16, 2016. The attraction, near the Myanmar border, started collecting the animals 15 years ago when villagers brought an injured tiger cub to the local abbot, who agreed to care for it. Today there are nearly 150 tigers at the monastery. (Photo by Amanda Mustard/The New York Times)

The sun rises over St Mary's Lighthouse in Whitley Bay on the Northumberland coast as a flock of Lapwing seabirds fly past on Wednesday, September 30, 2015. (Photo by Owen Humphreys/PA Wire)

A visitor falls down as they run away from a wave caused by a tidal bore which surged past a barrier on the banks of Qiantang River, in Hangzhou, Zhejiang province, China, October 28, 2015. (Photo by Reuters/China Daily)