South Korean teenagers participate in a warfare exercise as part of the Special Warfare Command's training course at a military base on August 4, 2011 in Seoul, South Korea. About 1,000 civilian volunteers including middle and high school students participated in the special force's four-day training programme to develop their spiritual and physical strength. (Photo by Chung Sung-Jun/Getty Images)

Balloons participate in the Balloon Spectacular during Canberra Festival on March 10, 2012 in Canberra, Australia. The annual balloon festival in Canberra is considered one of the best in the world, and is unique in allowing patrons to float above Parliament, embassies and other government buildings. Canberra is celebrating its 99th birthday in 2012, with over 50 events in the 17 day Canberra Festival. (Photo by Cameron Spencer/Getty Images)

In this undated photo provided by the North Korean government, North Korean leader Kim Jong Un tries a weapon during his three-day inspection from Aug. 3 until August 5, 2023 at major munitions factories in North Korea. Independent journalists were not given access to cover the event depicted in this image distributed by the North Korean government. The content of this image is as provided and cannot be independently verified. Korean language watermark on image as provided by source reads: “KCNA” which is the abbreviation for Korean Central News Agency. (Photo by Korean Central News Agency/Korea News Service via AP Photo)

Revellers celebrate moments before the rocket fire or “Txupinazo” marks the start of the Festival of San Fermin (or Sanfermines) at Consistorio square in Pamplona, Spain, 06 July 2014. The annual nine day long running-with-the-bulls fiesta commemorates St. Fermin, Pamplona's patron saint. (Photo by Javier Lizin/EFE)

Burundian refugees gather on the shores of Lake Tanganyika in Kagunga village in Kigoma region in western Tanzania with their belongings, as they wait for MV Liemba to transport them to Kigoma township, May 17, 2015. Burundi's embattled President Pierre Nkurunziza sacked his defense and foreign ministers on Monday, five days after surviving an attempted coup by generals opposed to his bid for a third term in office. (Photo by Thomas Mukoya/Reuters)

A man paddles a makeshift boat along a flooded street in Guasdualito, in the state of Apure, Venezuela, July 4, 2015. A total of 9,000 families have been affected by the overflowing of rivers Arauca and Sarare in Guasdualito, Apure state, because of the heavy rains in recent days in this area of the country, local media reported. (Photo by Carlos Eduardo Ramirez/Reuters)

Balloons are inflated at the Bristol International balloon fiesta in south west England August 6, 2015. Now in its 37th year, the Bristol International Balloon Fiesta is Europe's largest annual hot air balloon event in the city that is seen by many balloonists as the home of modern ballooning. (Photo by Toby Melville/Reuters)