Fred Fugen seen training for a jump over Austria on May 12, 2014. Fearless skydivers jump from an altitude of 10,000 meters above the largest mountain in Europe. Frederic Fugen, 34, and Vincent Reffet, 29, leapt from a plane in the freezing skies above Mont-Blanc in the French Alps. The jump is from such a height the pictures show the curvature of the earth. (Photo by Dominique Daher/Barcroft Media)

A two-horse team street cleaner, with sprayer, squeegee, and roller at rear. New York, between ca. 1910 and ca. 1915. (Photo by NYC Municipal Archives)

Krystian Herba, a Polish extreme cyclist jumps up the steps of Eureka Tower on a bicycle as he breaks a Guinness World Record at Eureka Tower on February 4, 2014 in Melbourne, Australia. Herba jumped up 2,919 steps on his bicycle in 1 hour 45 minutes without supporting himself with his hands or feet to break his own Guinness World Record. (Photo by Scott Barbour/Getty Images)

A participant jumps during the Red Bull Jump and Freeze competition at the ski resort of Gudauri, Georgia, March 20, 2016. (Photo by David Mdzinarishvili/Reuters)

“A skydiver has made history by smashing the world record for the highest skydive after leaping from 128,097ft (39,044m). Daredevil Felix Baumgartner ascended to the edge of space in a pressurised capsule suspended beneath a giant helium balloon. He then jumped out, freefalling for four minutes and 19 seconds before opening his parachute”.

Photo: Baumgartner celebrates after successfully completing the jump. (Photo by Balazs Gardi/Red Bull Stratos)

Britain's BASE jumper Sam Hardy lives up to his name after throwing himself off the top of the 335m-high Kuala Lumpur Tower during the KL Tower International Jump in Kuala Lumpur, Malaysia, Saturday, September 27, 2014. BASE stands for the places such jumpers usually jump from: buildings, antennas, spans (bridges) and earth (cliffs). (Photo by Lai Seng Sin/AP Photo)

Documentary photographer William E. Crawford was one of the first Western photographers to gain access to North Vietnam after the war ended. He has photographed the capital, Hanoi, at regular intervals since 1985, concentrating on the colonial and indigenous architecture, urban details, landscapes and intimate portraits of people in their home settings, street scenes and the city’s surrounding countryside. Here: 54 Hàng Ga (Chicken Street), 1994. (Photo by William E. Crawford from the book “Hanoi Streets 1985-2015: In the Years of Forgetting”)

Pro-government fighters stand next to a tank destroyed during recent fighting in Yemen's southwestern city of Taiz March 14, 2016. (Photo by Anees Mahyoub/Reuters)