An infrared portrait from NASA's Spitzer Space Telescope which shows generations of stars is seen in this undated NASA handout image released February 14, 2013. In this wispy star-forming region, called W5, the oldest stars can be seen as blue dots in the centers of the two hollow cavities (other blue dots are background and foreground stars not associated with the region). Red shows heated dust that pervades the region's cavities, while green highlights dense clouds. (Photo by NASA/Reuters/JPL-Caltech/Harvard-Smithsonian/Handout)

Robert Burck, a street performer known as “The Naked Cowboy” dips a woman as he poses for a photo in Times Square in New York, U.S., August 4, 2016. (Photo by Carlo Allegri/Reuters)

Retired builder Vasili Sidamonidze, 70, poses for a portrait at his home in Gori, Georgia, December 6, 2016. “Unfortunately, Stalin is not popular nowadays. Our people don't respect him. Only we, members of the (Communist) Party, respect him”, Sidamonidze said. “I always try to attend Stalin's birthday anniversaries in Gori. Unfortunately many people don't want to join us even if they live nearby. They look at us from their windows”. (Photo by David Mdzinarishvili/Reuters)

In this February 2, 2015 photo, tourists jump as they pose for a picture, after disembarking from the Ocean Nova cruise ship, on King George Island, Antarctica. This tourist season, which runs November through March, more than 37,000 visitors are expected to walk on the coldest continent on Earth, about 10 percent more than the year before. (Photo by Natacha Pisarenko/AP Photo)

In this Monday, March 16, 2015 photo, Syrian refugee Samira Helal, 17, who is two months pregnant, poses for a portrait at inside her tent at an informal tented settlement near the Syrian border, on the outskirts of Mafraq, Jordan. Nearly 3.8 million Syrians have fled their country and are now registered as refugees, according to the U.N. Most face increasingly desperate circumstances. (Photo by Muhammed Muheisen/AP Photo)

A man yells for help minutes after a Serb shell hit a crowded pedestrian walkway in Sarajevo, May 1993. Radovan Karadzic, a 70-year-old former psychiatrist, still in robust health, is the most senior political figure to be convicted by the International Criminal Tribunal for the Former Yugoslavia. He was found guilty of 10 out of 11 charges. He was acquitted of a second count of genocide in Bosnian towns. (Photo by Reuters)

A photo made available on 14 March 2016 shows a Thai villager takes selfie photograph on drought parched land at the dried up Mae Chang reservoir in Lampang province, northern Thailand, 12 March 2016. The ruined village including ancient temple had been underwater for 34 years since the Mae Chang reservoir was built in 1982, the area has now re-emerged after water in the reservoir dried up caused by the severe drought. Thailand is facing the worst drought in decades hardest hit by El Nino phenomenon combined with seasonal hot weather. (Photo by Rungroj Yongrit/EPA)

A woman carries earthen pots to fill them with drinking water on a hot summer day, on the outskirts of Ajmer, Rajasthan, India April 25, 2017. (Photo by Himanshu Sharma/Reuters)