Police take part in a role play exercise as they clear a protest on top of a train during training on March 6, 2012 in Oxenhope, England. A new team of specialist officers set up to deal with searches and policing at a height, such as on top of a train, undergo training exercise in Oxenhope, West Yorkshire. (Photo by Bethany Clarke/Getty Images)

Matt Town of the st Centingas historic re-enactment group poses for portraits in his home while wearing his replica Saxon armour on October 12, 2016 in Ramsgate, England. This weekend marks the 950th anniversary of 1066, the Battle of Hastings and the Norman Conquest, and many historical groups will be participating in a large-scale re-enactment on the site of the original battle. (Photo by Leon Neal/Getty Images)

Military helicopters fly in formation above a billboard with a picture of China's late Chairman Mao Zedong during a training session for the upcoming parade marking the 70th anniversary of the end of World War Two, on the outskirts of Beijing, July 2, 2015. Troops from Russia and Mongolia will march together with Chinese forces in a parade in Beijing in September to commemorate the end of World War Two, the government and state media said on Thursday, confirming the first two foreign participants. (Photo by Jason Lee/Reuters)

15-year old American girl Donica Streling meets with members of SHINee (샤이니) at SM Entertainment head office on June 20, 2012 in Seoul, South Korea. Donica, diagnosed with Charcot-Marie-Tooth disease, visited Seoul, South Korea to meet her favorite K-pop groups SHINee and Super Junior after finding hope in listening to Korean pop. (Photo by Chung Sung-Jun)

Photographer and artist Jill Greenberg poses at her home to promote her Exhibit “Glass Ceiling: American Girl Doll” And Billboard For LA on September 29, 2011 in Los Angeles, California. (Photo by Frazer Harrison/Getty Images)

In 1949, LIFE magazine sent famed photographer Nina Leen to document the daily life of a sassy troupe of young women who had run off and joined the famous Barnum & Bailey Circus in Sarasota, Fla. What developed was a portrait of a sisterhood formed over acrobatics that mixed high-flying wire acts with fashionable high-waisted shorts. Sarasota was once considered “the home of the American circus”. Here: an aerialist smoking while rehearsing for the Ringling Bros. and Barnum & Bailey Circus in Sarasota, FL in 1949. (Photo By Nina Leen/Time Life Pictures/Getty Images)

In this March 22, 1975 file photo, a refugee clutches a baby as a government helicopter gunship carries them away near Tuy Hoa, Vietnam, 235 miles northeast of Saigon. They were among thousands fleeing from Communist advances. AP Photographer Nick Ut will be retiring from the AP in March 2017 after 51 years of taking photographs from the front lines of the Vietnam War to the red carpets of Hollywood. (Photo by Nick Ut/AP Photo)