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

Schoolchildren perfom during celebrations to mark 35 years of Zimbabwe's Independence at the National sports stadium in Harare, Saturday, April 18, 2015. President Robert Mugabe, 91, the central figure in Zimbabwean politics 35 years after Independence from Britain, has led the country since 1980. (Photo by Tsvangirayi Mukwazhi/AP Photo)

Model Adriana Lima attends Madonna presents An Evening of Music, Art, Mischief and Performance to benefit Raising Malawi at Faena Forum on December 2, 2016 in Miami Beach, Florida. (Photo by Jeff Kravitz/FilmMagic for Raising Malawi)

Female bodybuilders compete in the annual Muscle Beach Championship bodybuilding and bikini competition at Venice Beach, California on September 7, 2015. Muscle beach Venice is one of two historic bodybuilding locations and took over as the most famous spot when the nearby Santa Monica Muscle beach was shutdown due to overcrowding. California Governor and actor Arnold Schwarzenegger used to be a regular amongst the many famous bodybuilders and actors who have trained there and still makes an occasional appearance. (Photo by Mark Ralston/AFP Photo)

Women labourers work at the construction site of a road in Kolkata January 8, 2015. Across towns and cities in India, it is not uncommon to see women cleaning building sites, carrying bricks and or shoveling gravel – helping construct the infrastructure necessary for the country's economic and social development. They help build roads, railway tracks, airports, and offices. They lay pipes for clean water supplies, cables for telecommunications, and dig the drains for sewage systems. But although women make up at least 20 percent of India's 40 million construction workers, they are less recognized than male workers with lower pay and often prone to safety hazards and sexual harassment. They are often unaware of their rights or scared to complain, say activists now trying to campaign for better treatment of women in the construction industry. (Photo by Rupak De Chowdhuri/Reuters)

An Afghan woman fills containers with water near her temporary shelter at an internally displaced person's (IDP) camp on the outskirts of Herat, Afghanistan, January 21, 2015. Dozens of families are living in temporary shelters even in harsh winters and most depend on aid distributions by the United Nations High Commissioner for Refugees (UNHCR). (Photo by Jalil Rezayee/EPA)

An Afghan refugee girl shows her younger brother a calf in a slum on the outskirts of Islamabad, Pakistan, Friday, February 6, 2015. (Photo by Muhammed Muheisen/AP Photo)

British rally driver Kris Meeke jumps his Citroen over a brow during the fifth special stage of the World Rally Championship (WRC) Rally of Australia, near Bellingen on the New South Wales central coast on September 12, 2014. (Photo by William West/AFP Photo)