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)

Genzebe Dibaba of Ethiopia competes in the women's 1500m semi-final during the 15th IAAF World Championships at the National Stadium in Beijing, China August 23, 2015. (Photo by Lucy Nicholson/Reuters)

Bjorn, aged 5, smiles as he poses with a Owl butterfly during an event to launch the Sensational Butterflies exhibition at the Natural History Museum in London, Britain March 23, 2016. The exhibition opens to the public on March 24 and runs until September 11. (Photo by Dylan Martinez/Reuters)

Rita Ora strips down to promote the new Tezenis lingerie range on December 7, 2016. The British singer, 26, shows off her curves in the latest campaign for the Italian brand. (Photo by Splash News/Tezenis)

Egyptian President Hosni Mubarak speaks to the media after talks with German Chancellor Angela Merkel at the Chancellery on April 23, 2008 in Berlin, Germany. (Photo by Sean Gallup/Getty Images)

British prime minister Winston Churchill (1874–1965) stops to pet a cat at Liverpool Street Station, 24th May 1952. (Photo by Keystone/Hulton Archive/Getty Images)

A man dressed as a zombie poses during the Thrill The World 2009 event, which sees fans from all over the world dance simultaneous to Michael Jackson's “Thriller” at Luna Park on October 25, 2009 in Sydney, Australia. (Photo by Brendon Thorne/Getty Images)

A rainbow appears over the Louisiana gulf May 26, 2010 in the Gulf of Mexico near Brush Island, Louisiana. (Photo by Win McNamee/Getty Images)