President Barack Obama watches as Joey Hudy (L), 14, from Phoenix, Arizona pumps the Extreme Marshmallow Cannon he invented, while touring student science fair projects on exhibit in the State Dining Room at the White House February 7, 2012 in Washington, DC. Obama hosted the second White House Science Fair celebrating the student winners of science, technology, engineering and math (STEM) competitions from across the country. (Photo by Molly Riley-Pool/Getty Images)

“Environmental Migrants: The Last Illusion” by photographer Alessandro Grassani, documents the life of people in Kenya, Mongolia and Bangladesh who migrate to escape environmental stresses to the city of their own countries in hopes for a better life. Here: Asia, Mongolia, March 27, 2011. A view of Ulaan Baator over the shoulder of a slumbering drunk. Alcoholism is a huge problem in the city, home to almost half of Mongolia's people. The capital's population has doubled in the past two years. High levels of unemployment and poverty await herders who abandon rural areas and arrive in the city, illiterate and untrained in any skills necessary for urban jobs. (Photo by Alessandro Grassani)

Russian Mi-28N from the Berkuty (Golden Eagles) helicopter display team fly in formation during the “Aviadarts” military aviation competition at the Dubrovichi range near Ryazan, Russia, August 2, 2015. The aircraft started dipping down due to back propeller failure and crashed, killing one of two pilots, according to a Reuters photographer and official representatives of the competition. The aviation contest is part of the International Army Games, which are held in Russia from the 1st till the 15th of August with participants from 17 countries, according to organizers. (Photo by Maxim Shemetov/Reuters)

From Tibetan monks playing basket ball with ice thawing high up in the Himalayas, to the pollution that hides behind the Taj Mahal, here’s pick from 60 exceptional environmental photographs, by photographers and filmmakers from 70 countries, that will go on show at the Royal Geographical Society in London from 29 June to 21 August. The winners will be announced on 28 June. Here: Gravel Workmen of Chittagong, Bangladesh, by Faisal Azim. Gravel workmen look through a glass window at a gravel-crushing yard in Chittagong. Full of dust and sand, it is an extremely unhealthy environment for working, but still hundreds of people work here for their livelihoods. (Photo by Faisal Azim/2016 Atkins CIWEM Environmental Photographer of the Year)

This picture taken on February 18, 2017 shows a customer holding a crested black macaque in Tomohon market in northern Sulawesi, Indonesia. Authorities and activists are stepping up efforts to persuade villagers on Sulawesi island to stop consuming the critically endangered crested black macaques, one of many exotic creatures that form part of the local indigenous community' s diet. The macaque' s meat is prized by the ethnic Minahasan people, a largely Christian group in the world' s most populous Muslim- majority country, who have no reservation about eating exotic animals, unlike Indonesia' s Islamic communities. (Photo by Bay Ismoyo/AFP Photo)

A policer officer hits a man with a baton as he tries to maintain order while migrants wait for trains at a temporary camp near Gevgelija, Macedonia, September 7, 2015. Several thousand migrants in Macedonia boarded trains on Sunday to travel north after spending a night in a provisional camp. Macedonia has organised trains twice a day to the north border where migrants cross into Serbia to make their way to Hungary. Since June, Macedonian authorities have said that more than 60,000 migrants have entered the country, and around 1,500 entered just in one day, mainly refugees from Syria. (Photo by Stoyan Nenov/Reuters)

Ray Yang, a celebrity trainer, takes a selfie before the start of a workout session during TV program "The Body Show" at a gym in Seoul, September 19, 2015. Looks no longer centre only on the face in beauty-obsessed South Korea, where more women are hitting the gym to improve muscle tone and physical health. As the ideal of beauty evolves in a country that is a trendsetter in cosmetics and the pursuit of plastic surgery, women's fitness has become a growth business, say purveyors of health products, from diet supplements to dumb-bells. (Photo by Kim Hong-Ji/Reuters)

Female metro passengers hold flowers presented to them by metro workers, prior to International Women's Day in Kiev, Ukraine, 02 March 2016. The hustle and bustle of the morning commute is broken up by an unexpected surprise. The first passengers to step on the train receive – a warm welcome and a pot of flowers. One woman says, “It's very nice. All the running around and then you're given a flower, it's not often. It's very nice. I'm going to take care of this flower”. International Women's Day first emerged from the activities of labour movements at the turn of the twentieth century, in North America and across Europe, it is celebrated on March 08 in many countries around the world. (Photo by Sergey Dolzhenko/EPA)