A picture released by the North Korean Central News Agency (KCNA) shows Kim Jong-un convening an urgent operation meeting at 0:30 am on March 29, 2013 at an undisclosed location, in which he ordered strategic rocket forces to be on standby to strike US and South Korean targets at any time. (Photo by KCNA via EPA)

A tourist jumps inside an upside-down house at Fengjing Ancient Town, Jinshan District, south of Shanghai, May 1, 2014. The upside-down house was built as a tourist attraction using everyday household items and furniture. (Photo by Aly Song/Reuters)

Amundsen-Scott South Pole Station experiences months of darkness. The sun dips below the horizon on March 21, after which follows several weeks of twilight before complete darkness results. Photo taken on June 25, 2009. (National Science Foundation/Jeremy Johnson)

A ten days old South American sea lion pup sits next to its mother Lunita at the “Tiergarten Schoenbrunn” Zoo in Vienna, Austria, July 28, 2015. The pup was born in the zoo and weighs about 14 kilograms (30 pounds). (Photo by Leonhard Foeger/Reuters)

A Russian-made rifle, carried by this woman when she was captured in Nearby Brush, is slung around her neck by South Vietnamese soldiers before they began their interrogation of her as Viet Cong suspect near AP La Ghi in Vietnam, August 25, 1965. The girl behind the woman, also was captured in the brush. (Photo by AP Photo)

Large waves break at Burleigh Heads on the Gold Coast,, Queensland, Australia, 05 June 2016. Recent wild weather unleashed heavy rainfalls, powerful winds and abnormally high tides in Southeast Queensland and northern New South Wales. (Photo by Dan Peled/EPA)

2016 Rio Olympics, Swimming, Preliminary, Men's 100m Backstroke, Heats, Olympic Aquatics Stadium, Rio de Janeiro, Brazil on August 7 2016. Christopher Reid (RSA) of South Africa competes. (Photo by Dominic Ebenbichler/Reuters)

Entomologist Anna Platoni wears a hat made of tropical flowers made by florist Emma Reynolds with a Blue Morpho butterfly on her cheek to mark the opening of Butterflies in the Glasshouse at RHS Garden Wisley, south of London, on Janurary 15, 2016. (Photo by Luke MacGregor/PA Wire/RHS)