A workman smooths out the gravel near the base of British artist Alex Chinneck' latest sculpture “A bullet from a shooting star” on the Greenwich Peninsula in London on September 17, 2015. The 35-metre tall, upside-down electricity pylon overlooks the Canary Wharf financial district. (Photo by Leon Neal/AFP Photo)

A Wiesel combat vehicle of the German Bundeswehr armed forces takes part in a demonstration for visitors prior to military exercises on September 28, 2011 near Munster, Germany. The Bundeswehr has instituted far-reaching changes in recent years, including an end to compulsory military service. (Photo by Sean Gallup/Getty Images)

Francisco Solano poses for a photo in his bird-feather suit after attending a Mass commemorating the feast day of St. Francis Solano, in Emboscada, Paraguay, Friday, July 24, 2015. Some 500 people attended the festivity – a mix of indigenous and Guarani Indian beliefs. The festival begins with a Mass, continues with a procession of the diminutive wooden statue of St. Francis, and ends with people dancing in suits made with black, white, brown and grey feathers. (Photo by Jorge Saenz/AP Photo)

Developed for the British American Ambulance Corps, this new motorcycle ambulance is capable of speeding wounded soldiers 90 miles an hour from the front lines to field hospitals. Its springs are synchronized with the patient's heartbeat to avoid increasing fever when traveling over various Terrain. Viewing it in New York August 27, 1941, are left to right: constable Herbert Scott of England, driver; William E. Detlor, whose firm developed the vehicle; M. W. Stand, inspector-general of Civilian Defense, and Maj. Edward Riekert, also. (Photo by AP Photo)

Londoners sleep on the platform and on the train tracks at Aldwych Underground station,London, during heavy all night Nazi bombing raids, October 8, 1940. (Photo by AP Photo)

A zoo employee carries three-month-old female giant panda cub, born to mother Liang Liang and father Xing Xing, on display to the public for the first time at the national zoo in Kuala Lumpur, Malaysia, November 17, 2015. (Photo by Olivia Harris/Reuters)

Visitors wear shirts with an image of former Chinese leader Mao Zedong at the Shanghai World Expo site in Shanghai, May 2, 2010. (Photo by Aly Song/Reuters)

Indonesian mahouts (elephant masters) bathe elephants prior to a daily patrol at a Conservation Respons Unite (CRU) to control elephant-human conflicts in Serbajadi, East Aceh on April 7, 2016. Elephants have joined the front line in the fight against poaching and illegal logging in the dense jungles of Sumatra. Guided by their Indonesian mahouts, they trek alongside rivers, over rough terrain and deep into the rainforest in an area that is home to numerous endangered species, from orangutans to tigers, but which has suffered devastating deforestation in recent years. (Photo by AFP Photo/Januar)