Girls dressed up in traditional Egyptian clothes from the early 20th century pose for a picture before they get their photos taken on the historical Al-Moez street of Islamic Cairo, Egypt, January 17, 2016. (Photo by Asmaa Waguih/Reuters)

A fighter belonging to Jaish al-Islam (Islam Army) runs to take cover near the frontline on March 14, 2016 in the neighbourhood of Jobar, on the eastern outskirts of the capital Damascus. (Photo by Amer Almohibany/AFP Photo)

Hotel staff practice self-defence skills after a training session given by team member of Special Weapons and Tactics (SWAT) team, in Hangzhou, Zhejiang province, April 7, 2016. (Photo by Reuters/Stringer)

People play on a beach along the Arabian Sea on a hot summer day in Mumbai, India, April 29, 2016. (Photo by Danish Siddiqui/Reuters)

A Naga sadhu, or naked Hindu holy man, poses for a picture after taking a holy dip in the Godavari River during Kumbh Mela, or Pitcher Festival, at Trimbakeshwar in Nasik, India, Sunday, September 13, 2015. Hindus believe taking a dip in the waters of a holy river during the festival, will cleanse them of their sins. According to Hindu mythology, the Kumbh Mela celebrates the victory of gods over demons in a furious battle over a nectar that would give them immortality. (Photo by Rafiq Maqbool/AP Photo)

An Iraqi Muslim woman walks past Christmas decorations for sale in the Shiite holy city of Najaf on December 17, 2015. (Photo by Haidar Hamdani/AFP Photo)

A woman strikes a police truck with her hand during a protest march in Santiago, Chile, Thursday, April 16, 2015. Thousands of students marched through the streets of Chile's capital to protest recent corruption scandals and to complain about delays in a promised education overhaul. While it was largely peaceful, violence broke out at the end when hooded protesters threw rocks and gasoline bombs at police. (Photo by Luis Hidalgo/AP Photo)

Soviet Army soldiers sit on their tanks in front of the Czechoslovak Radio station building in central Prague during the first day of Soviet-led invasion to then Czechoslovakia on August 21, 1968. (Photo by Libor Hajsky/Reuters)