U.S. soldiers wrestle with South Korean soldiers in a muddy ring during a joint ranger training exercise at a ranger camp near the demilitarised zone (DMZ) June 25 2003 in Paju, South Korea. (Photo by Chung Sung-Jun/Getty Images)

Jason Arnold, project manager from solarcentury walks between lines of solar panels erected at Weighbridge, Wheal Jane, Baldhu on July 7, 2011 near Truro, England. A ceremony was held today to mark the connection of the 1.4kw solar farm, which on a 6.2 acre plot is the first in the South West and biggest in the UK to date, using 5,680 panels. (Photo by Matt Cardy/Getty Images)

A South Korean woman looks out at the flood water after a torrential rain storm hit the capital city on July 27, 2011 in Seoul, South Korea. South Korea issued a national crisis warning on as torrential rain caused flooding in parts of the country, killing over 35 with at least ten missing. (Photo by Chung Sung-Jun/Getty Images)

South Korea's Amry Special Warfare Command (SWC) soldiers aim their machine guns in a frozen river during a winter exercise in Pyeongchang, South Korea, Thursday, January 8, 2015. About 200 SWC soldiers participated in this routine two-week winter drill. (Photo by Ahn Young-joon/AP Photo)

Vehicles clog a highway during a hazy day in Beijing, China, Wednesday, February 26, 2014. Beijing remained cloaked in hazardous white pollution hiding much of its skyline Wednesday, despite the announced closures or production cuts at 147 of the city's industrial plants. (Photo by Ng Han Guan/AP Photo)

Locals push a freezer after looting it from a shop, believed to be owned by a foreigner, during service delivery protests in Mohlakeng, west of Johannesburg, February 4, 2015. Local media reported that violence broke out on Wednesday morning when locals barricaded roads and burnt tyres during a service delivery protest. (Photo by Siphiwe Sibeko/Reuters)

The buffalo bull charges, on March 23, 2014, in Addo Elephant National Park, South Africa. A young elephant calf tried to attack an old buffalo bull and was taught a lesson it will never forget. The calf was with its herd at a watering hold Addo Elephant National park, South Africa, when the buffalo ventured towards the water. The elephant ran towards the buffalo but the larger animal picked up the young calf and tossed it four metres in the air. Luckily, the elephant was not hurt, but its pride was seriously injured. (Photo by Conrad Cramer/Barcroft Media)

In this photo taken Wednesday, November 26, 2014 attack dogs and their handlers apprehend a “rhino poacher” center, after alighting from a helicopter into water, in a simulation exercise showing training at an academy run by the Paramount Group, near Rustenburg, South Africa. The course prepares canine units to find firearms or contraband, track suspects in the undergrowth and abseil in harnesses from helicopters in pursuit of poachers. Dogs and handlers learn to trust each other and fine tune a relationship balancing control and aggression. (Photo by Denis Farrell/AP Photo)