In this Thursday, April 11, 2013 photo, North Korean female soldiers stand watch on the river bank of the North Korean town of Sinuiju, opposite to the Chinese border city of Dandong. (Photo by AP Photo)

A truck is seen in a hole after part of the structure of a bridge collapsed into a river in Changchun, Jilin province May 29, 2011. Two truck passengers were injured, while the cause of the accident is still under investigation, local media reported. (Photo by Reuters/China Daily)

Li Yuming, a local farmer who is interested in scientific invention, works on his unfinished miniature submarine “Xiaguang V” on the outskirts of Wuhan, capital of central China's Hubei province August 24, 2007. “Xiaguang V”, which is 3-metre long, 1.2-metre in height, has a maximum diving depth of 20 metres, and can hold two adults and one child at the same time. The submarine will be used for tour after safety test, local media said. (Photo by Reuters/Stringer)

A North Korean soldier kicks a pole along the bank of Yalu River near the North Korean town of Sinuiju, opposite the Chinese border city of Dandong, February 4, 2014. (Photo by Jacky Chen/Reuters)

The Villarrica Volcano is seen at night in Chile, April 16, 2016. Villarrica is one of Chile's most active volcanoes. Picture taken with long exposure. (Photo by Cristobal Saavedra/Reuters)

A woman and a child walk past the remains of collapsed houses damaged during the April 2015 earthquake, in Bhaktapur, Nepal March 18, 2016. The two devastating earthquakes that struck Nepal last year killed almost 9,000 people across the country. Inside the Kathmandu Valley almost 2,000 died, and some of the area's most important cultural and heritage sites were completely destroyed. As Kathmandu inhabitants prepare to mark the one-year anniversary of the event, thousands are still displaced and millions are living in temporary shelters. (Photo by Navesh Chitrakar/Reuters)

The Air2 (Air Squared) floating Bluetooth speaker from Axxess CE is displayed at CES Unveiled, the opening event for the media preview days at the 2015 Consumer Electronics Show, January 4, 2015 in Las Vegas, Nevada. The speaker which levitates over its own base is one of the winners for the CES Innovation Awards and is patent pending. (Photo by Robyn Beck/AFP Photo)

An attendee tries Acton's RocketSkates at the 2015 International CES at the Sands Expo and Convention Center on January 6, 2015 in Las Vegas, Nevada. The motorized skates that you strap to your shoes are powered by Lithium Ion batteries and can go up to 12 mph. (Photo by Ethan Miller/Getty Images)