Max Gold, 20, of NYC, cruises on his skateboard as thousands gather on the National Mall for the March for Science on Saturday, April 22, 2017, in Washington, DC. Activists and scientists descend on the nation's capital to rally for environmental causes and government policies rooted in scientific research as part of the Earth Day and March for Science rallies. (Photo by Jahi Chikwendiu/The Washington Post)

Crown line handler Bobby Marie controls “Chain Gang” as the balloon is inflated during the 43nd Annual Helen to the Atlantic Balloon Race and Festival, in Helen, Georgia, USA, 04 June 2016. The race is the oldest balloon event in the southern USA and United States' only long-distance hot air balloon race, according to the organizers. (Photo by Erik S. Lesser/EPA)

Kyaiktiyo, Burma, 1978. The Golden Rock at Shwe Pyi Daw (the Golden Country), the Buddhist holy place. Hiroji Kubota writes: “I was desperate to keep a distance from America for a while; luckily, I found Burma and its gentle and compassionate people. In the spring of 1978, on the top of the hill where I took this photo, I had two Leica bodies: the one with Tri-X and the other with Kodachrome 64. Soon after, I realised that the colour one looked very colourful and was more powerful. That was my decisive moment, to become a colour photographer”. (Photo by Hiroji Kubota/Magnum Photos)

Children are engulfed by foam during the Bubble Show event in Beijing, China, Sunday, June 26, 2016. Thousands of residents enjoy colored foam churned out by machines along a running track at the event designed for children and parents' interaction. (Photo by Ng Han Guan/AP Photo)

A young man, who says he is part of a local criminal gang, poses for a picture holding a gun in the neighbourhood of Korogcho in Nairobi, Kenya, March 19, 2015. Around 2 million people live in the shantytowns packed in around Kenya's capital. Crime is high amid chronic unemployment levels, while basic services and sanitation are scarce. Residents try to make the best of things, eking out a living and picking up work where they can. (Photo by Siegfried Modola/Reuters)

Artist Emiliano Paolini (R), and his partner Marianela Perelli, show their “Ken” doll that they have re-designed into the religious figure of Jesus Christ at their workshop in Rosario, north of Buenos Aires September 23, 2014. Paolini and Perelli have adapted religious figures such as Jesus Christ, Moses and the Virgin of Guadalupe to Mattel's line of Barbie and Ken dolls and are working on more religious figures, although they say they will not be using the Prophet Muhammad to avoid controversy. They plan to have a gallery show in Buenos Aires next October. (Photo by Enrique Marcarian/Reuters)

An Afghan journalist takes a “selfie” as U.S. President Barack Obama (R) holds a joint news conference with Afghanistan's President Ashraf Ghani (C) at the White House in Washington March 24, 2015. (Photo by Jonathan Ernst/Reuters)

Mud Madness at the annual Jaffa Cakes charity three-mile run at Foymore Lodge near Portadown this afternoon, on April 13, 2014. A total of a thousand competitors and fun-runners took part in the two races held over the mudstrewn endurance course. (Photo by Alan Lewis/Photopress Belfast)