Dogs, Pretty, Llilly, and Rocky wait for their turn to be examined by veterinarians during a community campaign for the sterilisation and deworming of dogs and cats in Havana, Cuba February 25, 2016. (Photo by Reuters/Stringer)

Female Kurdish Peshmerga take part their graduation ceremony at a police academy in Zakho district of the Dohuk Governorate of the Iraqi Kurdistan province, Iraq March 30, 2016. (Photo by Ari Jalal/Reuters)

A Palestinian man rides his horse on a beach in Gaza City February 17, 2017. (Photo by Mohammed Salem/Reuters)

Cake made by Gisela Prekau on display at the Cake International show at Alexandra Palace in London, UK on April 22, 2017. Cake International 2017, the Cake Decorating and Baking Show, takes place over the weekend at Alexandra Palace, North London featuring giant cakes, moving cakes, stunning crafter cakes, exquisitely detailed cakes and the latest ranges of cake decorating products and accessories, college displays and workshops. (Photo by Dinendra Haria/Rex Features/Shutterstock)

Pamukkale, Turkey, is home to these terrace pools, formed by the build-up of carbonate mineral from the warm water flowing from the thermal springs above. (Photo by Image Courtesy of Jennifer Hayes/Getty Images)

Pod of dolphins surf effortlessly through the waves in the wild traveling at speeds up to 20 mph. (Photo by Greg Huglin)

Spectators in Moscow were treated to the site of humorously designed makeshift aircraft plunging into the Muskova River during the Red Bull Flugtag Moscow 2011 competition. 38 teams took part at the Flugtag – which means “flying day” – a competition in which teams in fancy dress attempt to pilot human-powered, home-made flying machines off a six-meter-high platform into water.

Photo: A makeshift aircraft plummets into the Moskva River during the Red Bull Flugtag Moscow 2011 competition. (Photo by Sergei Karpukhin/Reuters)

German flying ace Baron Manfred von Richthofen (1892–1918) also known as The Red Baron with his dog Moritz, circa 1916.