“NASA's Pathfinder, Pathfinder Plus, Centurion and Helios Prototype were an evolutionary series of solar- and fuel-cell-system-powered unmanned aerial vehicles. AeroVironment, Inc. developed the vehicles under NASA's Environmental Research Aircraft and Sensor Technology (ERAST) program. They were built to develop the technologies that would allow long-term, high-altitude aircraft to serve as “atmospheric satellites”, to perform atmospheric research tasks as well as serve as communications platforms”. – Wikipedia

Photo: The solar-electric Helios Prototype flying wing is flies over the Hawaiian islands of Niihau and Lehua during the first solar-powered test flight July 14, 2001 from the U.S. Navy's Pacific Missile Range Facility on Kauai, HI. The 18-hour flight was a functional checkout of the aircraft's systems and performance in preparation for an attempt to reach sustained flight at 100,000 feet altitude later in the summer. (Photo Courtesy of NASA/Getty Images)

One of the two wooden rafts of the Kon-Tiki II expedition is prepared at the port of Callao prior to the departure to Pascua island in Chile, in Callao, Peru, October 30, 2015. Fourteen men from various parts of the world set out on rafts to commemorate the Norwegian navigator Thor Heyerdahl expedition 68 years ago. The original raft crossed the Pacific Ocean from South America to the Polynesian Islands. This rafts are a replica of ships used 6,000 years ago, but will be equipped with solar panel. (Photo by Mariana Bazo/Reuters)

Body surfers ride a large wave at the Wedge in Newport Beach of the Southland coast on May 20, 2011 in Newport, California. Surfers have been lured to the south facing beaches for the biggest swells of the season. (Photo by Kevork Djansezian/Getty Images)

Birds behaviour winner: Land of the Eagle by Audun Rikardsen, Norway. High on a ledge, on the coast near his home in northern Norway, Rikardsen carefully positioned an old tree branch that he hoped would make a perfect golden eagle lookout. To this, he bolted a tripod head with a camera, flashes and motion sensor attached, and built himself a hide a short distance away. From time to time, he left road‑kill carrion nearby. Very gradually – over the next three years – a golden eagle got used to the camera and started to use the branch regularly to survey the coast below. (Photo by Audun Rikardsen/2019 Wildlife Photographer of the Year)

Foghorn Stringband – Reuben's Train. Foghorn Stringband is an old-time string band from Portland, Oregon, United States. They are considered one of the finest old-time string bands on the West Coast.

A photographer has shot this series of scenic selfies – scaling freezing mountain tops to snap himself in front of stunning scenery. Paul Zizkas breath-taking work features himself in front of beautiful backdrops such as shimmering lakes, snowy mountains and vibrant auroras. He has travelled to a number of different locations worldwide including Canada, New Zealand, Niue the South Pacific and French Polynesia. Explorer Paul, from Banff, Alberta, Canada, saw his selfies go viral early in 2014 – and has now unveiled his latest work. He said: I find that sometimes including a person in a landscape scene adds to the photograph – that it conveys a different story. Here: lake Minnewanka, Banff National Park, Alberta, Canada. (Photo by Paul Zizkas/Caters News)

In this November 18, 2014 photo, Murshida, 12, sits on the lap of her mother Marjina as the train leaves for their village in West Bengal, at a railway station in New Delhi, India. Six months ago, Marjina stepped off a train in New Delhi with her two children, hoping to find a better life after her husband abandoned them without so much as a goodbye. The family spent their days at a landfill picking through other people’s garbage to find salvageable bits to resell or recycle. After six months of poverty, illness and shame, they returned to that train station in New Delhi, headed back to an uncertain future to their hometown in West Bengal. (Photo by Altaf Qadri/AP Photo)