Visitors look at graffiti art created by Brazilian artist Image during the 3rd annual Graffiti Fine Art Biennial International exhibit, at the Pavilion of Brazilian Cultures, in Sao Paulo, Brazil, Tuesday, April 21, 2015. The month-long event features the work of more than 60 street artists, representing 11 countries. (Photo by Andre Penner/AP Photo)

A white Bengal tiger cub plays with its mother in a zoo in the Siberian city of Novosibirsk, about 2,800 kilometers (1,750 miles) east of Moscow, Russia, Tuesday, April 21, 2015. Two blue-eyed Bengal tiger cubs were born in March to a couple of white tigers at Novosibirsk zoo. (Photo by Ilnar Salakhiev/AP Photo)

Members of the Barrio 18 gang run upon their arrival to the San Francisco Gotera penitentiary April 21, 2015. The Salvadoran goverment transfered 1,177 inmates, members of the Barrio 18 gang from Izalco jail to San Francisco Gotera in a effort to curb gang violence activity, according to local media. (Photo by Jose Cabezas/Reuters)

Festival-goers enjoy the mud during the annual Boryeong Mud Festival at Daecheon Beach on July 18, 2015 in Boryeong, South Korea. The mud, which is believed to have benefical effects on the skin due to its mineral content, is sourced from mud flats near Boryeong and transported to the beach by truck. (Photo by Chung Sung-Jun/Getty Images)

Cylists hang to the back of a truck outside the capital Bujumbura, July 19, 2015, as the country awaits next week's presidential elections. Each day scores of cyclists make the 45 kilometer downhill journey at breakneck speed from Bugarama to sell bananas, often hanging from the back of trucks for the return uphill trip. (Photo by Mike Hutchings/Reuters)

North Korean leader Kim Jong Un smiles as he attends a flight training session by female fighter pilots Jo Kum Hyang and Rim Sol in this undated photo released by North Korea's Korean Central News Agency (KCNA) on June 22, 2015. (Photo by Reuters/KCNA/Antara Foto)

Elvis Presley tribute artist Bruce Stewart (L) of Georgian Bay, Ontario passes Lorenz Francke of Scarborough, Ontario during the four-day Collingwood Elvis Festival in Collingwood, Ontario July 25, 2015. Featuring over 120 Elvis tribute artists, it is the world's largest Elvis festival and last year hosted 30,000 visitors. (Photo by Chris Helgren/Reuters)

A man wearing an armor attends a reenactment of the Battle of Agincourt, in Agincourt, northern France, Saturday, July 25, 2015. The French are hosting a reenactment of the clash with England this weekend. More than 800 people in Medieval garb are gathering at the site to commemorate the battle, which was a turning point in the Hundred Years' War. (Photo by Thibault Camus/AP Photo)