Omsin, a 25 year old femal green sea turtle, rests next to a tray of coins that were removed from her stomach after a surgical operation at the Faculty of Veterinary Science, Chulalongkorn University in Bangkok, Thailand, March 6, 2017. (Photo by Athit Perawongmetha/Reuters)

Students pose for a picture with a 3- D optical illusion artwork of a devastated cityscape in Aleppo, Syria at the campus of the Meiji University in Tokyo on November 18, 2016. The Japanese branch of the human rights organisation Amnesty International displayed the artwork to encourage people to think about the Syrian civil war. (Photo by Toshifumi Kitamura/AFP Photo)

A combination of four pictures shows participants dressed in superhero and heroic fantasy costumes posing during the second edition of the Hero Festival in Marseille, France, November 7, 2015. The festival is dedicated to American superhero comics, Japanese mangas, heroic fantasy characters and video games universes. (Photo by Jean-Paul Pelissier/Reuters)

In this Wednesday, June 8, 2016 photo, Joe Giles, an actor portraying a zombie in “The Walking Dead”, poses with social media reporter Danielle Datu during a walker boot camp at Universal Studios Hollywood in Los Angeles. (Photo by Jae C. Hong/AP Photo)

American model Cindy Crawford, 55, recreated her famous Pepsi advert from 1992 for the University of Wisconsin’s Cancer Care Unit. Limited edition prints of the model, shot by the photographer David Yarrow, have a $40,000 price tag and have raised $1 million. (Photo by David Yarrow Photography)

Students from St Andrews University are covered in foam as they take part in the traditional Raisin Weekend in the Lower College Lawn, at St Andrews in Scotland on October 22, 2018. The “raisin weekend” stems from a gift of raisins (now flour and foam) traditionally given by a first year student to their academic “parents” in gratitude for their guidance. (Photo by Russell Cheyne/Reuters)

US President Donald Trump and First Lady Melania Trump watch the Florida Atlantic University Marching Band and cheerleaders perform prior to a Super Bowl party at Trump International Golf Club in West Palm Beach, Florida, February 4, 2018. (Photo by Saul Loeb/AFP Photo)

British theoretical physicist Stephen Hawking, Cambridge University Professor and Fellow, circa 1985. Stephen Hawking, the brightest star in the firmament of science, whose insights shaped modern cosmology and inspired global audiences in the millions, has died aged 76. (Photo by Gemma Levine/Getty Images)