Disguised revellers parade on the occasion of the Cortege during the Carnival in Basel, Switzerland, February 17, 2016. (Photo by Georgios Kefalas/EPA)

“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)

Desmond Boylan, a photographer who covered war and conflict across the world before dedicating his life to documenting the daily joys and tribulations of life in Cuba for Reuters and The Associated Press, died suddenly while on assignment on Saturday, December 29, 2018 afternoon in Havana. Here: Cuban President takes a glass during a ceremony in the Oporto Bourse where he and other Ibero-American leaders were made members of the Port Wine Brotherhood in Portugal, October 1998. (Photo by Desmond Boylan/Reuters)

Italian artist Maurizio Cattelan poses with his creation “Him” (2001) prior to the opening of the exhibition “Not Afraid of Love” at the Hotel de la Monnaie in Paris, France, October 17, 2016. From October 21, 2016 to January 8, 2017, “Not Afraid of Love”, curated by Chiara Parisi, director of Cultural Programs, sets Maurizio Cattelan’s “comeback at work” in one of the most beautiful Palaces on the river Seine. (Photo by Philippe Wojazer/Reuters)

A woman dressed for la “La Diablada” festival walks down a road in Pillaro, Ecuador, Friday, January 6, 2017. Local legend holds that anyone who adopts a costume for the celebration and wears it at the event six years in a row will have good luck. (Photo by Dolores Ochoa/AP Photo)

Revelers jump on a rainbow painted crosswalk in Church Street, Toronto's LGBT neighbourhood, before “WorldPride”, a gay pride parade, in Toronto, June 29, 2014. Toronto is hosting WorldPride, a week-long event that celebrates the lesbian, gay, bisexual and transgender (LGBT) community. (Photo by Mark Blinch/Reuters)

Porcelain Black performs during the ' I Am Still Music' Tour at the Wells Fargo Center on March 26, 2011 in Philadelphia, Pennsylvania