Students hold their weapons before the swearing in ceremony for the military students, in Bucharest, Romania, Wednesday, October 25, 2017. The Romanian Army is proudly celebrating their Army Day and marking 100-years since the landmark battle of Marasesti, a key World War I battle in 1917 when Romanian and Russian soldiers defeated German troops, halting a German offensive. (Photo by Vadim Ghirda/AP Photo)

A participant wearing a costume poses for members of the public before the 40th anniversary of the Sydney Gay and Lesbian Mardi Gras Parade in central Sydney, Australia, March 3, 2018. (Photo by David Gray/Reuters)

Female members of the Chinese People's Liberation Army (PLA) honour guard stand behind a string to ensure that they are in a straight line before a welcoming ceremony for Russian President Vladimir Putin outside the Great Hall of the People in Beijing, China, June 25, 2016. (Photo by Kim Kyung-Hoon/Reuters)

Personal trainer, Denise Austin, and Katie Austin arrive at the ESPY Awards at the Microsoft Theater on Wednesday, July 13, 2016, in Los Angeles. (Photo by Jordan Strauss/Invision/AP Photo)

2016 Rio Olympics, Judo, Final, Women, 48 kg Bronze Medal Contests, Carioca Arena 2, Rio de Janeiro, Brazil on August 6, 2016. Otgontsetseg Galbadrakh (KAZ) of Kazakhstan and Dayaris Mestre Alvarez (CUB) of Cuba react. (Photo by Kai Pfaffenbach/Reuters)

MTV Ex On The Beach and reality TV Star Jemma Lucy is spotted keeping herself in shape with a workout session in a park in Manchester, UK on September 2, 2016. (Photo by XposurePhotos.Com)

Mr. Zhong Hua, of Johns Hopkins University School of Medicine, took this image of the peripheral nerves (those outside of the brain) in an 11.5-day-old mouse embryo, magnified five times. (Photo by Zhong Hua)

Early morning shark Sean McKeon pictured during severe flooding Oliver Plunkett street, Cork city, on February 3, 2014. (Photo by Daragh McSweeney/Provision)