Afghan air force 2nd Lt. Niloofar Rhmani walks the flight line at Shindand Air Base, Afghanistan, prior to her graduation from undergraduate pilot training, on May 13, 2013. Rhmani made history on May 14, when she became the first female to successfully complete undergraduate pilot training and earn the status of pilot in more than 30 years. She will continue her service as she joins the Kabul Air Wing as a Cessna 208 pilot. (Photo by Senior Airman Scott Saldukas/USAF)

Nazi dictator Adolf Hitler greets supporters at a May Day gathering in the Olympic Stadium, Berlin. (Photo by Keystone). 1st May 1938

Students from the University of St Andrews jump into The North Sea, as a good luck tradition before exams start on the East Sands in St Andrews, Fife, Scotland on May 1, 2018. (Photo by Derek Allan/Alamy Live News)

Fifty years ago, as France exploded in mass protests, words scrawled on the walls of the Sorbonne summed up the revolutionary zeal of the time: “Run free, comrade, we’ve left the old world behind!”. Sexual liberation, artistic creativity and anti-capitalism were the order of the day. For those who were there, it was an unforgettable time. Here: A wounded student is transported by first-aid workers during riots on the Boulevard Saint-Michel, Paris, France on May 6, 1968. (Photo by Gökşin Sipahioğlu/SIPA Press)

A reveller walks through the streets in the early hours during traditional May Day celebrations in Oxford, Britain, May 1, 2015. (Photo by Dylan Martinez/Reuters)

A Loggerhead sea turtle named Gal Handless is moved into a large case at the rescue center for sea turtles as it is transferred to the Istanbul Aquarium on May 29, 2013 in Michmoret, Israel. The turtle was rescued after losing her front fins when caught in a fishing net in 2004. She was rehabilitated at the rescue center but could not be returned back to the sea and now after 9 years she is being transferred to her new home at the Istanbul Aquarium in Turkey. (Photo by Uriel Sinai)

Contestants prepare backstage during the Angel of Turkey transgender/transsexual beauty pageant in Istanbul, Turkey, late May 26, 2016. (Photo by Murad Sezer/Reuters)