Soviet Army soldiers sit on their tanks in front of the Czechoslovak Radio station building in central Prague during the first day of Soviet-led invasion to then Czechoslovakia on August 21, 1968. (Photo by Libor Hajsky/Reuters)

People take pictures of 30 Rockefeller Plaza as it is lit in the colors of the Democratic and Republican parties ahead of the U.S presidential election in Manhattan, New York, U.S., November 7, 2016. (Photo by Andrew Kelly/Reuters)

Indian Air Force soldiers toss their rifles as they perform during the full-dress rehearsal for Indian Air Force Day at the Hindon air force station on the outskirts of New Delhi October 6, 2015. (Photo by Anindito Mukherjee/Reuters)

Julia Wheeler, 31, from Perth, Western Australia, has been a hands reach away from pilot whales, Bull sharks, manta rays and more during her time diving without any breathing equipment. Here real life mermaid Julia is diving with manta rays in Bali and looks incredible swimming among them while holding her breath for four and a half minute. (Photo by Julia Wheeler/Caters News Agency)

Actors dressed as Santa Claus take a refreshing bath at Bellevue Beach north of Copenhagen, Denmark, on July 24, 2018, as they take part in the World Santa Congress, an annual two-day event held every summer in Copenhagen. (Photo by Mads Claus Rasmussen/AFP Photo/Ritzau Scanpix)

A storm is seen in Sarasota, Florida, June 24, 2018. (Courtesy of Val Vasilescu/Facebook.com/Kingofsunsets via Reuters)

Two hippopotamus are fed with pumpkins at the Hanoi Zoo, in Hanoi, Vietnam, 25 October 2018. The zoo has been the home for more than 800 animals of over 90 different species, including three hippopotamus, since it was built in 1976. (Photo by Luong Thai Linh/EPA/EFE)

Cosplay fans attend the Animation Comic Games (ACG) Culture Festival in Xi'an, capital of northwest China's Shaanxi Province, May 28, 2017. The festival kicked off on Saturday, attracting lots of cosplay fans. (Photo by Liu Xiao/Xinhua)