Seven-year-old Mimi Meade winces from the sting as Dr. Richard Mulvaney inoculates her April 26, 1954 in McClean, Va., with the new Salk polio vaccine. Mrs. John Lucas, a registered nurse, holds Mimi's arm steady as she gets one of the first injections of the countrywide test. (Photo by Harvey Georges/AP Photo)

A delegate dressed in a furry Lion costume walks across a Zebra crossing to the convention centre at the Eurofurence convention in Berlin on August 17, 2017. Some 2700 delegates are taking part in the 3-day-long Eurofurence in the German capital, the worlds oldest active Furry-convention for people dressing up in furry costumes. (Photo by Odd Andersen/AFP Photo)

A Somali Armed Forces member carries her ammunition during fighting between the military and police backed by intelligence forces in the Dayniile district of Mogadishu, Somalia September 16, 2017. (Photo by Feisal Omar/Reuters)

A woman rides the world's longest urban zip line, with a speed of up to 80 kilometers per hour on a one kilometer run from 170 meter to ground level, in the Marina district of Dubai, United Arab Emirates, Tuesday, December 5, 2017. (Photo by Kamran Jebreili/AP Photo)

A worker loads palm fruit at a palm oil plantation in North Mamuju regency, West Sulawesi province, Indonesia March 10, 2016 in this photo taken by Antara Foto. (Photo by Sahrul Manda Tikupadang/Reuters/Antara Foto)

A woman offers a prayer at Pashupatinath Temple during the Teej festival in Kathmandu, Nepal September 4, 2016. During this festival, married Hindu women observe day-long fast and pray for a happy married life while those unmarried pray for a good husband. (Photo by Navesh Chitrakar/Reuters)

A boat is stranded on Poyang Lake in Lushan City, China during low-water season on November 3, 2016. (Photo by Xinhua/Barcroft Images)

A man flies a dragon-shaped kite at a square on March 31, 2006 in Changchun of Jilin Province, China. (Photo by China Photos/Getty Images)