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

A boy flies his kite in a cemetery in the Vila Operaria Favela of Rio de Janeiro, Brazil, July 9, 2016. (Photo by Nacho Doce/Reuters)

Participants struggle to reach the prizes during a greased-pole climbing competition held as a part of the independence day celebrations in Jakarta, Indonesia, Sunday, August 17, 2014. Indonesia is celebrating its 69th independence from the Dutch colonial rule. (Photo by Dita Alangkara/AP Photo)

Wally Collins holds a bust of author Ernest Hemingway after winning the 2014 “Papa” Hemingway Look-Alike Contest in this handout photo provided by the Florida Keys News Bureau at Sloppy Joe's Bar in Key West, Florida July 19, 2014. Collins, a Phoenix resident, won the title on his sixth try during the event that was the highlight of Key West's annual Hemingway Days festival. (Photo by Andy Newman/Reuters/Florida Keys News Bureau)

Mount Sinabung is seen during an eruption from Surbakti village in Karo, North Sumatra, Indonesia, April 20, 2015. The local government is preparing the relocation of residents from three of the villages that were destroyed. (Photo by Tibta Pangin/Getty Images/Anadolu Agency)

Two biplanes of the Team Breitling cross during a training flight prior the AIR14 air show in Payerne, Switzerland, August 29, 2014. (Photo by Peter Schneider/EPA)

A competitor shows her tattoos at the MBK Tattoo Contest in a shopping mall in Bangkok October 23, 2014. (Photo by Athit Perawongmetha/Reuters)

A pro-Russian activist aims a pistol at supporters of the Kiev government during clashes in the streets of Odessa May 2, 2014. Police said a man was shot dead in clashes between a crowd backing Kiev and pro-Russian activists in the largely Russian-speaking southern port of Odessa, which lies west of Crimea, annexed by Moscow in March. (Photo by Yevgeny Volokin/Reuters)