Steam enthusiasts demonstrate their engines at the Great Dorset Steam Fair, the biggest event of its kind in Europe on September 2, 2011 in Tarrant Hinton, near Blandford, England. Over 200,000 people are expected to attend the 600 acre event, which is in its 43rd year and includes displays and demonstrations of steam and vintage machinery over five days. (Photo by Matt Cardy/Getty Images)

The BMW i8 concept vehicle is displayed at a sneak preview of the car along with the BMW i3 on November 9, 2011 in New York City. (Photo by Spencer Platt/Getty Images)

A member of Iraqi rapid response forces fires a rocket launcher during a battle with Islamic State militants in the district of Yarimja in southern Mosul, Iraq, January 18, 2017. (Photo by Alaa Al-Marjani/Reuters)

The worst drought in 40 years has a cruel grip on Somalia. A struggling young government and militant violence have compounded to bring crisis to 6.7 million lives. The town of Baidoa is facing some of the harshest conditions. Surrounded by territory controlled by al-Shabaab militants and amid ongoing attacks, 160,000 people have had to leave their farms and are surviving in camps where hunger, thirst and cholera await them. (Photo by Peter Caton/Mercy Corps)

A reveller smiles as she walks in the rain at Worthy Farm in Somerset during the Glastonbury Festival in Britain, June 28, 2015. (Photo by Dylan Martinez/Reuters)

A glass skywalk in Wanyuan, Sichuan province, built along the side of a cliff, is the highest such skywalk anywhere in China on January 31, 2017. Some visitors have been proven to be terrified by the experience had to brace against the wall in fear. (Photo by Chinanew.com/AsiaWire)

A passenger not wearing pants sits in a subway train during the “No Pants Subway Ride” in Prague, Czech Republic, January 10, 2016. The event is an annual flash mob and occurs in different cities around the world in January, according to its organisers. (Photo by David W. Cerny/Reuters)

A woman cartwheels through the Coachella Valley Music and Arts Festival in Indio, California April 10, 2015. (Photo by Lucy Nicholson/Reuters)