An Aden civilian crouching in terror as British soldiers threaten him during Arabian demonstrations in Crater. (Photo by Express Newspapers/Getty Images). 1967

A worker pauses for a sandwich, resting on a girder during the construction of a skycraper. (Photo by Hulton Archive/Getty Images). Circa 1930

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

The Burney, a new streamlined car on the London streets, designed by Sir Denniston Burney who was responsible for the design of the R100 (R 100) airship. The engine is in the rear. (Photo by Topical Press Agency/Getty Images). 15th September 1930

A long time exposure shows a Igloo at the “Igloo village” (Iglu Dorf) in front of the famous Matterhorn mountain in Zermatt, Switzerland, late 28 January 2016. The hotel-igloo village made of snow and ice at 2'815 meters about sea level with a bar, a restaurant, bedrooms and wellness are celebrating their 20th anniversary. For this occasion the hosts built the largest classic igloo with a diameter of 13 meters and a ceiling hight of 11 meters in front of Matterhorn in Zermatt, and they will attempt the world record for this Igloo. (Photo by Jean-Christophe Bott/EPA)

A walker has left a handprint on a snow- covered tree trunk on Grosser Feldberg mountain in the Taunus mountain range, Germany, 16 January 2017. (Photo by Frank Rumpenhorst/DPA)

A weapon is being destroyed during an exercise to disable seized weapons in Caracas, Venezuela August 17, 2016. (Photo by Marco Bello/Reuters)

Model Juliana Paesthe (C) of Viradouro samba school participates in the annual carnival parade in Rio de Janeiro's Sambadrome, February 15, 2015. (Photo by Ricardo Moraes/Reuters)