Tourists wearing protective face masks walk in Nanluoguxiang alley, a famous touristic spot at Hutong neighborhood, in Beijing, China, 01 May 2020. China is loosening up nationwide restrictions after months of lockdown over the coronavirus crisis. Labor Day in the country kicked off with a long weekend and an extended holiday, from 01 to 05 May, after the tourism industry has been hit during the coronavirus and COVID-19 disease pandemic. (Photo by Roman Pilipey/EPA/EFE)

A mural painting by graffiti artist Eme Freethinker features likenesses of US President Donald Trump (R) and Chinese premier Xi Jinping wearing face covers in Berlin on April 28, 2020 amid the new coronavirus COVID-19 pandemic. (Photo by John Macdougall/AFP Photo)

Visitors enjoy food at a table bounded by a banner with a character fast food restaurant Kentucky Fried Chicken, in Jakarta, Indonesia, on June 23, 2020. The display banner is useful for limiting physical distance for visitors who eat on the spot. The Indonesian government has imposed a new set of regulations known as “new normal”, which will be implemented in stages starting in early June for some provinces. (Photo by Jefta Images/Barcroft Media via Getty Images)

Actors dressed as zombies and ghouls perform during a drive-in haunted house show by Kowagarasetai (Scare Squad), for people inside a car in order to maintain social distancing amid the spread of coronavirus, at a garage in Tokyo, Japan on July 3, 2020. (Photo by Issei Kato/Reuters)

An Indonesian jockey rides two bulls with a cart during a traditional sport bull race locally called “pacu jawi” in Pariangan of Tanah Datar regency in West Sumatra on December 1, 2018. (Photo by Adek Berry/AFP Photo)

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)

“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)

A white Bengal tiger cub plays with its mother in a zoo in the Siberian city of Novosibirsk, about 2,800 kilometers (1,750 miles) east of Moscow, Russia, Tuesday, April 21, 2015. Two blue-eyed Bengal tiger cubs were born in March to a couple of white tigers at Novosibirsk zoo. (Photo by Ilnar Salakhiev/AP Photo)