Couples kiss during a kissing contest in Wuhan, Hubei province, November 23, 2014. Some 20 couples attended the contest and the winners have been awarded an iPhone 6, according to local media. (Photo by Reuters/Stringer)

Rooftops of solar powered houses are pictured in Ota, 80 km northwest of Tokyo in this October 28, 2008 file photo. One by one, Japan is turning off the lights at the giant oil-fired power plants that propelled it to the ranks of the world's top industrialised nations. With nuclear power in the doldrums after the Fukushima disaster, it's solar energy that is becoming the alternative. Solar power is set to become profitable in Japan as early as this quarter, according to the Japan Renewable Energy Foundation (JREF), freeing it from the need for government subsidies and making it the last of the G7 economies where the technology has become economically viable. (Photo by Yuriko Nakao/Reuters)

Members of the “Exit Point” amateur rope-jumping group jump from a 44-metre high (144-ft) waterpipe bridge in the Siberian Taiga area outside Krasnoyarsk, September 13, 2015. Rope-jumping, an extreme sport, involves jumping from a high point using an advanced leverage system combining mountaineering and rope safety equipment. (Photo by Ilya Naymushin/Reuters)

Londoners sleep on the platform and on the train tracks at Aldwych Underground station,London, during heavy all night Nazi bombing raids, October 8, 1940. (Photo by AP Photo)

A zoo employee carries three-month-old female giant panda cub, born to mother Liang Liang and father Xing Xing, on display to the public for the first time at the national zoo in Kuala Lumpur, Malaysia, November 17, 2015. (Photo by Olivia Harris/Reuters)

A worker inspects the Christ the Redeemer statue which was damaged during lightning storms in Rio de Janeiro January 21, 2014. (Photo by Severino Silva/Reuters/Agência o Dia)

Plants grow on houses in the abandoned fishing village of Houtouwan on the island of Shengshan July 26, 2015. Just a handful of people still live in a village on Shengshan Island east of Shanghai that was once home to more than 2,000 fishermen. Every day hundreds of tourists visit Houtouwan, making their way on narrow footpaths past tumbledown houses overtaken by vegetation. The remote village, on one of more than 400 islands in the Shengsi archipelago, was abandoned in the early 1990s as first wealthy residents then others moved away, aiming to leave problems with education and food delivery behind them. (Photo by Damir Sagolj/Reuters)

Mrs. Marie Graskamp of Milwaukee shows the different positions one might assume when entering the bomb shelter in Milwaukee September 3, 1958. This circular entrance is about three feet in diameter. This is the entrance (according to the builders) that would connect to the cellar of a home assuming the shelter was in the ground for added protection. If a bombing should occur, all members of family would proceed to the cellar and then through the circular port into the shelter. (Photo by AP Photo)