People play Taiji on a square on August 08, 2011 in Luoyang, Henan Province of China. People all over China mark National Fitness Day on Monday in their own ways. (Photo by ChinaFotoPress/Getty Images)

Three workers demonstrating the different types of gas masks used in mine rescue work. (Photo by Fox Photos/Getty Images). December 1925

A fireman from the London Fire Brigade, wearing a smoke helmet. (Photo by Topical Press Agency/Getty Images). Circa 1908

Commuters walk up the redesigned subway stairs at the Tanjong Pagar subway station on August 23, 2011 in Singapore. The subway stairs have been repainted in bright colours and slogans encouraging people to take the stairs, by way of promoting fitness in the city. (Photo by Chris McGrath/Getty Images)

Women take part in Belarus Cup in bodybuilding and fitness in Minsk, October 24, 2015. (Photo by Vasily Fedosenko/Reuters)

A woman wearing a bikini stands next to fuel pumps as she waits to top up fuel at a petrol station in Kiev, Ukraine, September 26, 2015. One of the largest networks of petrol stations in Ukraine organized a campaign in which anyone who showed up in swimwear at a particular gas station during specified hours would receive free gasoline, according to representatives of the company. (Photo by Valentyn Ogirenko/Reuters)

Competitors prepare backstage before the 2015 Brazil Miss and Mister Fitness contest in Sao Paulo, Brazil, June 18, 2015. Some 96 men and women from all across the country competed in the event. (Photo by Paulo Whitaker/Reuters)

Palestinian Anoush Belian poses on stage during a bodybuilding competition in Tel Aviv, Israel August 22, 2015. Belian, from Jerusalem, on Saturday became the first Palestinian female bodybuilder to participate and win an Israeli competition. Belian won the Miss Fitness category in the competition organised by the National Amateur Bodybuilders Association (NABBA) in Israel. (Photo by Ammar Awad/Reuters)