A guard secures gates of a catfish farm visited by a group of foreign reporters in Pyongyang, North Korea April 17, 2017. (Photo by Damir Sagolj/Reuters)

An artist airbrushes a model during the “World Bodypainting Festival 2017” in Klagenfurt, Austria on July 28, 2017. (Photo by Leonhard Foeger/Reuters)

A tourist train is decorated with Christmas lights in Bogotá, Colombia on December 10, 2017. (Photo by Jaime Saldarriaga/Reuters)

Two women kiss each other during a flashmob on the ocassion of the International Day Against Homophobia, Transphobia and Biphobia in Pamplona, Navarra, Spain, 17 May 2017. The International Day Against Homophobia, Transphobia and Biphobia is held every year on 17 May. (Photo by Villar Lopez/EPA/EFE)

A reveller of the Salgueiro samba school performs during the second night of Rio's Carnival at the Sambadrome in Rio de Janeiro, Brazil, on February 13, 2018. (Photo by Mauro Pimentel/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)

A passenger without pants waits for the subway train during “The No Pants Subway Ride” in Mexico City January 11, 2015. The event, the fifth organized in Mexico, is an annual flash mob and occurs in different cities around the world, according to its organisers. (Photo by Edgard Garrido/Reuters)

A Ukrainian serviceman wearing a new year's hat waves at his comrades while standing beside his tank near Debaltseve, eastern Ukraine, February 8, 2015. (Photo by Gleb Garanich/Reuters)