A publican serves a glass of stout to a donkey in the East End of London, 1960s. (Photo by Steve Lewis/Getty Images)

A B-52 bomber is watched by a group of curious onlookers as it lands at RAF Fairford, February 21, 1999. The B52s arrived from the U.S.A. as part of NATO's preparations for air attacks on Yugoslavia as tensions in the Kosovo crisis increased. (Photo by Dylan Martinez/Reuters)

Handler Jorge Garcia-Bengochea holds Honor, a miniature therapy horse from Gentle Carousel Miniature Therapy Horses, as they visit with patients at the Kravis Children's Hospital at Mount Sinai in the Manhattan borough of New York City, March 16, 2016. Some of the most powerful medicine delivered to young patients at Mount Sinai Hospital in New York on Wednesday came in a package less than 32 inches tall and with a tail. Honor, a 10-month-old colt with Gentle Carousel Miniature Therapy Horses, trotted into the hearts of dozens of children and teens being treated at the Manhattan hospital. (Photo by Mike Segar/Reuters)

A tiger cub has a short chat with a chimp. (Photo by Ian Tyas/Keystone Features/Getty Images). 27th November 1979

A Leyland lorry during the railway strike, “we supply both milk and baby” is chalked on the bonnet. (Photo by A. R. Coster/Topical Press Agency/Getty Images). 3rd October 1919

Aerobatic pilot Sean D. Tucker flies in the two-seat Oracle Extra airplane over downtown Chicago skyline, Wednesday, June 8, 2016. Tucker will perform before the start of of the America's Cup World Series racing on Saturday and Sunday. (Photo by Kiichiro Sato/AP Photo)

The Queen Elizabeth Tower (Big Ben) is reflected in a puddle as a cyclist rides by in London, on 27 June 2016. Britain began preparations to leave the European Union on Monday but said it would not be rushed into a quick exit, as markets plunged in the wake of a seismic referendum despite attempts to calm jitters. (Photo by Leon Neal/AFP Photo)

A man stands on a mountain summit as he looks over the Inntal valley in the western Austrian village of Gnadenwald, Austria on July 18, 2017. (Photo by Dominic Ebenbichler/Reuters)