Two women look at a mobile phone as they stand on Tiananmen Square during a sand storm in heavily polluted weather in Beijing on February 28, 2013. Beijing residents were urged to stay indoors as pollution levels soared before a sandstorm brought further misery to China's capital. (Photo by Ed Jones/AFP Photo)

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)

July 23, 2013 – Kampala, Uganda. Helene and Diana train daily more than 2.5 hours by Innocent Kapalata, a passionate and ambitious former boxer. Amidst the shanty homes a group of ambitious fighters are trying to reach for a better life. (Photo by Peter Bauza/ZUMA Press/VISUAL Press)

This week's full Moon as photographed from on board the International Space Station by NASA astronaut Jeff Williams on August 19, 2016. Jeff is currently Commander of the Space Station for the Expedition 48 crew. (Photo by Jeff Williams/NASA)

Children, some in tears, are escorted down a road in Barcelona, Spain, Thursday, August 17, 2017. Police in Barcelona say a white van has mounted a sidewalk, struck several people in the city's Las Ramblas district. (Photo by Manu Fernandez/AP Photo)

A man from Dinka tribe holds his AK-47 rifle in front of cows in a Dinka cattle herders camp near Rumbek, capital of the Lakes State in central South Sudan December 14, 2013. (Photo by Goran Tomasevic/Reuters)

A resident walks past big waves spilling over a wall onto a coastal road in the city of Legaspi in Albay province, south of Manila on December 14, 2015, as typhoon Melor approaches the city. More than 700,000 people fled the central Philippines amid threats of giant waves, floods and landslides as powerful Typhoon Melor approached the archipelago nation, officials said December 14. (Photo by Charism Sayat/AFP Photo)

Chinese archaeologists announced the discovery of 110 life-sized terracotta warriors, guarding the tomb of Qin Shi Huang, China's first emperor.

Photo: Archaeologists work on a terracotta warrior in the third excavation of pit one at the Terracotta Warriors and Horses Museum in Xi'an in northwest China's Shaanxi province Saturday, June 9, 2012. (Photo by AP)