Sun Rongchun, 57, exercises with an improvised cervical traction device attached to a high bar at a sports complex in Shenyang, Liaoning province, China on April 9, 2019. (Photo by Sheng Li/Reuters)

An Iraqi shi'ite muslim girl places a copy of the Koran on her head during the holy month of Ramadan at the Imam Ali Shrine, in the holy city of Najaf, Iraq on May 28, 2019. (Photo by Alaa Al-Marjani/Reuters)

Students dressed up as Hindu gods Lord Krishna and Lord Shiva participate in a cultural event in their school in Mumbai, India on August 21, 2019. (Photo by Indranil Mukherjee/AFP Photo)

A Saudi woman holds a falcon as she participate for the first time in the 2nd Saudi Falcons and Hunting Exhibition in Riyadh, Saudi Arabia on October 16, 2019. (Photo by Ahmed Yosri/Reuters)

A home-made steam train, designed by Pavel Chilin, rides on a make-shift railway across country house neighborhood in the settlement of Ulyanovka in Leningrad region, Russia on November 4, 2019. (Photo by Anton Vaganov/Reuters)

A woman walks past the barbed wire separating Belarusian servicemen and Belarusian opposition supporters during a rally in Minsk, Belarus, Sunday, August 30, 2020. Tens of thousands of demonstrators have gathered in the capital of Belarus, beginning the fourth week of daily protests demanding that the country's authoritarian president resign. The protests began after an Aug. 9 presidential election that protesters say was rigged and officials say gave President Alexander Lukashenko a sixth term in office. (Photo by Tut.By via AP Photo)

Starlings are seen at their nesting box in a private garden in the town of Bobruisk, Belarus, April 8, 2018. (Photo by Vasily Fedosenko/Reuters)

“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)