This computer image provided Monday March 17, 2014 by the Press Office of socialist candidate to Paris Mayor Anne Hidalgo, shows a tunnel of abandoned railway from the 19th century, now ramshackle and overgrown, turned into a cinema. Hidalgo’s plan envisions not just a green space but in the tunnels, places for farming fish and mushrooms. (Photo by AP Photo/Anne Hidalgo's Press Office)

"Temptation", part of an installation from the artist-duo David Burns and Austin Young, appears among the works of 30 artists in the multimedia exhibition "The Value of Food: Sustaining a Green Planet" at the Cathedral of St. John the Divine, Wednesday, October 7, 2015, in New York. The exhibition, installed in the cathedral's seven chapels and 14 bays, explores food accessibility, sustainability and other food-related issues and runs through April 3, 2016. (Photo by Bebeto Matthews/AP Photo)

Pfc. Esmeralda Calderon stands and salutes the flag on the 15th green during the first round of the LPGA golf tournament at Kingsmill Resort and Golf Course in Williamsburg, Va., Thursday May 23, 2019. Pfc. Calderon, from San Antonio, Texas, is a Marine assigned to Naval Weapons Station Yorktown. (Photo by John Sudbrink/The Daily Press via AP Photo)

A man inspects a plastic cover placed over an artwork attributed to Banksy on May 17, 2012 in London, England. The stencilled image depicts a poor child making Union Jack flags on a sewing machine and is located on the wall of a Poundland discount shop in the Wood Green area of north London. (Photo by Peter Macdiarmid)

Artist Gaelle Villedary has installed a grass “carpet” across the village of Jaujac in France to celebrate the 10th anniversary of the Arts and Nature Trail program. The green trail is made of 168 rolls of grass and runs for 1,377 feet (420 metres) to connect the village seamlessly to its surrounding natural landscape.

“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)

The X-47B prototype on Tuesday flew off an aircraft carrier and into the history books. Today's achievement, the first-ever catapult launch of an unmanned aircraft from the flight deck of a carrier, promises to open up a new chapter in the annals of naval aviation. Photo: An X-47B pilot-less drone combat aircraft is launched for the first time off an aircraft carrier, the USS George H. W. Bush, in the Atlantic Ocean off the coast of Virginia, May 14, 2013. The U.S. Navy made aviation history on Tuesday by catapulting an unmanned jet off an aircraft carrier for the first time, testing a long-range, stealthy, bat-winged plane that represents a jump forward in drone technology. (Photo by Jason Reed/Reuters)