A student protester throws a stone against a riot police vehicle during a demonstration to demand changes in the education system in Santiago, Chile, April 21, 2016. (Photo by Ivan Alvarado/Reuters)

In this July 15, 2015 photo, Nepalese amputee victims Khendo Tamang, left, and Nirmala Pariyar, both 8, share a single pair of shoes at the Bir Trauma Center in Kathmandu, Nepal. After suffering serious leg wounds in Nepal's massive 2015 earthquake that killed and injured thousands, both girls were brought to the Bir Trauma Center in Kathmandu, to receive single leg amputations. Following their surgeries, Nirmala's relentless cheerfulness drew a still very depressed Khendo close and both found an inseparable friendship which has helped their emotional wounds heal. (Photo by Niranjan Shrestha/AP Photo)

Sichuan Opera performer Wu Yonghong, 26 years, of the Jinyuan Opera Company performs for villagers at the Dongyue Temple on May 2, 2016 in Cangshan, Sichuan province, China. Sichuan opera is a vibrant, centuries-old tradition that showcases the joys and challenges of daily life in rural China with tales of love, tradition, and family honor. Photo by Kevin Frayer/Getty Images)

An Indian villager tries to tame a bull during a traditional bull-taming festival called “Jallikattu”, in the village of Palamedu, near Madurai, Tamil Nadu state, India, Monday, January 15, 2018. Jallikattu involves releasing a bull into a crowd of people who attempt to grab it and ride it. (Photo by R. Parthibhan/AP Photo)

Student Rabindra Bharati University celebrates the Holi festival, Color Festival on February 26, 2018 in Kolkata, India. Holi, the popular Hindu spring festival of colours is observed in India at the end of the winter season on the last full moon of the lunar month, and will be celebrated on March 1 this year. (Photo by Debajyoti Chakraborty/NurPhoto via Getty Images)

Artists perform during the opening show directed by German director Volker Hesse, on the opening day of the Gotthard rail tunnel, at the fairground Rynaecht at the northern portal in Erstfeld, Switzerland, Wednesday, June 1, 2016. The construction of the 57 kilometer long tunnel began in 1999, the breakthrough was in 2010. After the official opening on June 1, the commercial operation will start in December 2016. (Photo by Ruben Sprich\Pool Photo via AP Photo)

U.S. Secretary of State John Kerry and Mongolian Foreign Minister Lundeg Purevsuren watch an archer during a Naadam ceremony, a competition which traditionally includes horse racing, Mongolian wrestling and archery, in Ulan Bator, Mongolia, June 5, 2016. (Photo by Saul Loeb/Reuters)

Bronze medalist Carlos Coloma Nicolas of Spain celebrates after finishing third in the cross-country cycling mountain bike race at the 2016 Summer Olympics in Rio de Janeiro, Brazil, Saturday, August 20, 2016. (Photo by Patrick Semansky/AP Photo)