Prince Philip, Duke of Edinburgh practicing his bicycle polo technique, Windsor Great Park, Berkshire, 1964. (Photo by Norman Potter/Daily Express/Hulton Archive/Getty Images)

A protester gestures during a “Yellow vest” protest against higher fuel prices during clashes on the Champs-Elysees in Paris, France, November 24, 2018. (Photo by Benoit Tessier/Reuters)

Bebe Rexha wears satin fuchsia suit while leaving The Tonight Show Starring Jimmy Fallon in New York City on December 20, 2018. (Photo by Felipe Ramales/Splash News and Pictures)

Young girls attend a training session in MGFSO Olympic reserve school in Moscow on May 30, 2016. (Photo by Kirill Kudryavtsev/AFP Photo)

Melania Trump during Melania Trump Unveils The 2007 Cadillac Escalade to The Fashion World at Milk Studios in New York City, New York, United States. (Photo by Jamie McCarthy/WireImage)

Budgies feed on seeds from a local visitor's hands at Ocean Park in metro Manila, Philippines September 10, 2016. (Photo by Romeo Ranoco/Reuters)

Roof-topping enthusiast Daniel Lau takes a selfie with high-rise buildings down below as he stands on the top of a skyscraper in Hong Kong, China on August 15, 2017. A craze that began in Russia has now taken hold in Hong Kong, one of the world's most vertical cities. Mr Lau said he had been inspired by Russian climbers and that he was unafraid of the vertiginous heights he scales. (Photo by ImagineChina/Rex Features/Shutterstock)

A walrus kisses a visitor during a sea animal show at the Hakkeijima Sea Paradise aquarium-amusement park complex in Yokohama, southwest of Tokyo, Monday, September 11, 2017. (Photo by Shizuo Kambayashi/AP Photo)