Women spray their designs on a wall during a graffiti class offered by the LATA 65 organization in Lisbon, Portugal May 14, 2015. The LATA 65 organization is an initiative for the elderly in the area of urban art. Since it began in 2012, they have introduced the world of graffiti to over 100 senior citizens, giving workshops in different neighborhoods of Lisbon. (Photo by Rafael Marchante/Reuters)

A woman works at a factory producing clay pots at Phu Lang pottery village in Bac Ninh province, Vietnam, May 14, 2015. The village is part of an old pottery triangle in northern Vietnam which includes Bat Trang and Tho Ha, and has been producing pottery since the 13th century, according to local media. (Photo by Reuters/Kham)

Partially constructed notched burial plots are seen at the construction site of an underground tunnel designated for traditional Jewish burial at the Givat Shaul cemetery, on May 14, 2015, in Jerusalem, Israel. Underground cemetery being built by the Israeli Burial Society in Jerusalem due to a decrease in available land for traditional Jewish burials. (Photo by David Vaaknin/The Washington Post)

Te Matatini Kapa Haka Aotearoa perform the Haka at the Edinburgh Festival Fringe on the Royal Mile on August 14, 2014 in Edinburgh, Scotland. The largest performing arts festival in the world, this years festival hosts more than 3,000 shows in nearly 300 venues across the city. (Photo by Jeff J. Mitchell/Getty Images)

14 week-old twin polar bear cubs play during their first presentation to the media in Hellabrunn zoo on March 19, 2014 in Munich, Germany. The male and female twins were born on December 9, 2013 in the zoo. (Photo by Alexandra Beier/Getty Images)

Afghan paraglider Leeda Ozori, 21, walks after practicing in Kabul, Afghanistan September 14, 2015. She is one of a group of young Afghans taking to the skies of a capital where military helicopters and surveillance balloons are a far more familiar sight. Women in Afghanistan's conservative Muslim society are increasingly entering areas such as education, sports and the workplace, but most still wear the head-to-toe garment, the burqa. (Photo by Mohammad Ismail/Reuters)

The Lumix GX1 single lens reflex (SLR) camera with 14-42 mm powerzoom lens is displayed at the Panasonic booth at the 2012 International Consumer Electronics Show at the Las Vegas Convention Center January 10, 2012 in Las Vegas, Nevada. The new camera comes with an external viewfinder and flash and an ISO up to 12,800. The camera as shown sells for USD 949; the camera body alone is USD 799. (Photo by Ethan Miller/Getty Images)

In this photo taken on Friday, July 14, 2017, a student at a paramilitary camp for children calls the rank to attention outside Kiev, Ukraine. As the deadly conflict in eastern Ukraine entered its third year, some parents in Ukraine are anxious to make sure their children are ready to fight it, instead of swimming and playing volleyball. (Photo by Efrem Lukatsky/AP Photo)