Dancers prepare before a performance in the backstage area of the Buick exhibition during the “Auto China 2014” Beijing International Automotive Exhibition in Beijing on April 21, 2014. Leading automakers have gathered in Beijing for the kickoff of China's biggest car show, but lackluster growth and environmental restrictions in the world's largest car market have thrown uncertainty into the mix. (Photo by AFP Photo)

A Buddhist monk salvages a statue of a Buddhist deity from a monastery around the famous Swayambhunath stupa after it was damaged by Saturday's earthquake in Kathmandu, Nepal, Thursday, April 30, 2015. In mere seconds, Saturday's earthquake devastated a swathe of Nepal. Three of the seven World Heritage sites in the Kathmandu Valley have been severely damaged, including Durbar Square with pagodas and temples dating from the 15th to 18th centuries, according to UNESCO, the United Nations cultural agency. (Photo by Niranjan Shrestha/AP Photo)

Villagers look on as Mount Sinabung volcano spews thick volcanic ash, as seen from Beganding village in Karo, North Sumatra province, on May 19, 2017. Sinabung roared back to life in 2010 for the first time in 400 years. After another period of inactivity, it erupted once more in 2013 and has remained highly active since. (Photo by Ivan Damanik/AFP Photo)

A Femen activist, Sarah Constantin, is hanged from a noose-like rope from a Paris bridge to call attention to the large number of executions in Iran as she stages a protest against visiting Iranian President Hassan Rouhani in Paris, Thursday, January 28, 2016. A near-naked woman hanging from a noose-like rope from a Paris bridge has sent a message to visiting Iranian President Hassan Rouhani. (Photo by Zacharie Scheurer/AP Photo)

Dancers audition for a post as cheerleaders of the Miami Dolphins, in Rio de Janeiro, Brazil, Thursday, March 3, 2016. Brazilian dancers audition in the first international cheerleader recruitment for the Miami Dolphins in Rio de Janeiro. The Dolphins will also hold auditions in Colombia, Argentina, Mexico and South of Florida. (Photo by Felipe Dana/AP Photo)

In this Wednesday, July 23, 2014 file photo, Omaha photographer Lane Hickenbottom photographs the night sky in a pasture near Callaway, Neb. With no moon in the sky, the Milky Way was visible to the naked eye. More than one-third of the world’s population can no longer see the Milky Way because of man-made lights, according to a scientific paper by Light Pollution Science and Technology Institute's Fabio Falchi and his team members, published on Friday, June 10, 2016. (Photo by Travis Heying/The Wichita Eagle via AP Photo)

A Ukrainian serviceman fires a 2S7 Pion self-propelled gun during military exercises near the village of Divychky in Kiev region, Ukraine, October 21, 2016. (Photo by Valentyn Ogirenko/Reuters)

Indian Air Force soldiers toss their rifles as they perform during the full-dress rehearsal for Indian Air Force Day at the Hindon air force station on the outskirts of New Delhi October 6, 2015. (Photo by Anindito Mukherjee/Reuters)