This picture taken on February 23, 2014 shows participants wearing dresses running half-naked in the annual 3.5 km Undie Run held in the Olympic Forest Park smog-covered Beijing. Some 200 participants took part in this event, many of them with gas masks, as dangerous smog blighted swathes of northern China in recent days. (Photo by AFP Photo/STR)

An F/A-18 Hornet assigned to Strike Fighter Squadron One Five One (VFA-151) emerges from a cloud created when it broke the sound barrier in the skies over the Pacific Ocean, July 7, 1999. (Photo by John Gay/US Navy)

Police walk past a burning car during riots in Birmingham City Centre on August 8, 2011 in Birmingham, England. After three nights of rioting and looting in and around London, the chaos is starting to spread to other cities around Britain. (Photo by Jeff J Mitchell/Getty Images)

A devotee offers prayers to the setting sun during the "Chhat" festival at Bagmati river in Kathmandu, Nepal November 17, 2015. Hindus in Nepal celebrate "Chhat", a four-day festival that honours the sun god, by praying at sunrise and sunset, and seek blessings for one's family by giving offerings. (Photo by Navesh Chitrakar/Reuters)

A woman rides a women-only bus as she returns from her college in Kathmandu January 6, 2015. Nepal's capital Kathmandu has introduced women-only buses in an attempt to reduce sexual harassment and groping on public transport, a senior government official said on Monday. The initiative will start with four 16-seater buses which will ply a popular east-west route across the city during peak morning and evening hours. (Photo by Navesh Chitrakar/Reuters)

Eighty one-year-old Sakon Haba (L) wearing loin cloth walks past a police station after he bathed in ice-cold water at the Teppozu Inari shrine in Tokyo January 11, 2015. According to organizers, about 100 participants took part in the Shinto ceremony to purify their souls and wish for good health in the new year. (Photo by Toru Hanai/Reuters)

Locals push a freezer after looting it from a shop, believed to be owned by a foreigner, during service delivery protests in Mohlakeng, west of Johannesburg, February 4, 2015. Local media reported that violence broke out on Wednesday morning when locals barricaded roads and burnt tyres during a service delivery protest. (Photo by Siphiwe Sibeko/Reuters)

Devotees attend the annual voodoo festival in Ouidah January 10, 2016. The national voodoo holiday in the West African country of Benin had a distinctively political accent this year as practitioners from Africa and the Americas gathered on Sunday to offer prayers and sacrifices for peace. Hundreds of followers of the traditional religion gathered in the Atlantic coast town of Ouidah, once an important port in the slave trade, to pray for calm during the tiny country's presidential election scheduled for February. (Photo by Akintunde Akinleye/Reuters)