A prototype Rollkers transportation device is displayed during a press event at the Mandalay Bay Convention Center for the 2015 International CES on January 4, 2015 in Las Vegas, Nevada. The product is not a skate; it balances for you and when you place it on the bottom of your shoe, it gives you the ability for faster transportation based on walking. The balance CES, the world's largest annual consumer technology trade show, runs from January 6-9 and is expected to feature 3,600 exhibitors showing off their latest products and services to about 150,000 attendees. (Photo by Ethan Miller/Getty Images)

“The Dream Chaser is a planned crewed suborbital and orbital vertical-takeoff, horizontal-landing (VTHL) lifting-body spaceplane being developed by SpaceDev, a wholly owned subsidiary of Sierra Nevada Corporation (SNC). The Dream Chaser design is planned to carry seven people to and from low earth orbit. The vehicle would launch vertically on an Atlas V and land horizontally on conventional runways”. – Wikipedia

Photo: NASA Deputy Administrator Lori Garver talks during a press conference with Sierra Nevada's Dream Chaser spacecraft in the background at the University of Colorado at Boulder on February 5, 2011 in Boulder, Colorado. Sierra Nevada's Dream Chaser spacecraft is under development with support from NASA's Commercial Crew Development Program to provide crew transportation to and from low Earth orbit. NASA is helping private companies develop innovative technologies to ensure that the U.S. remains competitive in future space endeavors. (Photo by Bill Ingalls/NASA via Getty Images)

Yang Juan, an employee at Goopal Group, takes a nap in her seat after lunch, in Beijing, China, April 21, 2016. Office workers sleeping on the job is a common sight in China, where a surplus of cheap labour can lead to downtime at work. But in China's technology sector, where business is growing faster than many start-up firms can hire new staff, workers burn the midnight oil to meet deadlines and compete with their rivals. Some companies provide sleeping areas and beds for workers to rest during late nights. (Photo by Jason Lee/Reuters)

Trainees of the Tianjiao Special Guard/Security Consultant bodyguard training camp watch their instructor use a scarf to cover a student's head during a demonstration of close-quarter combat skills at a special course on flight safety inside a scale model of a passenger jet at a flight attendant training centre on the outskirts of Beijing, March 18, 2014. Inspired by the missing Malaysia Airlines Flight MH370, the company wanted to emphasize the importance of aviation safety by teaching their trainees emergency evacuation procedures and close-quarter combat skills to handle situations such as natural disasters and plane hijacks, according to the company. (Photo by Jason Lee/Reuters)

Discovered in 1952 by French bio-speleologist Henri Coiffait, the waterfall and accompanying sinkhole were fully mapped in the 1980s by the Spéléo club du Liban. The cave is also known as the "Cave of the Three Bridges." Traveling from Laklouk to Tannourine one passes the village of Balaa, and the "Three Bridges Chasm" (in French "Gouffre des Trois Ponts") is a five-minute journey into the valley below where one sees three natural bridges, rising one above the other and overhanging a chasm descending into Mount Lebanon. During the spring melt, a 90–100-metre (300–330 ft) cascade falls behind the three bridges and then down into the 250-metre (820 ft) chasm. A 1988 fluorescent dye test demonstrated that the water emerged at the spring of Dalleh in Mgharet al-Ghaouaghir.

General view of the monument to memory of soldiers who liberated the city of Knin – in Knin, Croatia on November 10, 2014. Across the former Yugoslavia stand giant monuments to a state that no longer exists, once visited and celebrated during public holidays such as Republic Day on November 29, marking the creation of socialist Yugoslavia. Many are now neglected or ignored, aging symbols of a joint state forged during World War Two but torn apart by nationalism half a century later. Republic Day is no longer marked in any of the seven independent states that emerged from its ashes. (Photo by Antonio Bronic/Reuters)

In this photo taken Tuesday, February 2, 2016, asylum seekers gather round a fire as they cook a meal overlooking the temporary Altnes camp refugee camp on the island of Seiland, northern Norway. Waiting for their asylum claims to be processed, hundreds of people in emergency shelters in Hammerfest and neighboring towns are slowly getting used to the extreme climate and unfamiliar customs of the High North. They say they have adapted to the cold – the temperature rarely drops below minus 10 degrees C (14 F) along the coast, though it gets much colder further inland. It’s the darkness that throws them off. (Photo by Alastair Grant/AP Photo)

People work with cocoa beans in Enchi June 17, 2014. Picture taken June 17, 2014. Ghana emerged as a success story during the 2000s, when war, political instability and a disastrous liberalization brought Ivory Coast's cocoa sector to its knees. Ghana's output more than tripled from 340,000 tons in the 2001/02 season to a record 1,025,000 tons a decade later. Strict controls cemented its reputation as a producer of top quality beans, establishing a brand that fetches a premium. (Photo by Thierry Gouegnon/Reuters)