A Chesterfield Borough Police telephone operator tests a gasmask with built in earpiece and microphone. The telephone service is considered one of the most important links in the coordination of ARP operations and must remain operational during air raids, 12th April 1939. (Photo by Fox Photos/Hulton Archive/Getty Images)

A stray dog is pictured besides a graffiti made on a shutter of a closed shop at a market area during an ongoing state-wide weekend curfew imposed by the directive of the Delhi government to curb the spread of the Covid-19 coronavirus in New Delhi on January 9, 2022. (Photo by Sajjad Hussain/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)

People ride a minibus illuminated with green colorful lights at a street in preparation for celebrations of the birthday of the prophet Muhammad, in Sana'a, Yemen, 04 October 2022. Mawlid is annually celebrated by many Muslim countries on the 12th day of Rabi al-Awwal (the third month of the Islamic calendar), marking the birthday of the prophet Muhammad, which is expected to be marked on 08 October 2022. In Yemen, it is celebrated by illuminating buildings and streets with green colorful lights and decorating vehicles in green. (Photo by Yahya Arhab/EPA/EFE)

A model presents a creation by a Mexican designer during a catwalk show promoting diversity and inclusion to foster acceptance and removal of barriers that disabled people face in the country, in Mexico City, Mexico on October 26, 2022. (Photo by Quetzalli Nicte-Ha/Reuters)

Apollinariia Panfilova and Dmitry Rylov of Russia perform in the Pairs Short Program during day one of the ISU Grand Prix of Figure Skating Rostelecom Cup at Megasport Arena on November 20, 2020 in Moscow, Russia. (Photo by Evgenia Novozhenina/Reuters)

A group of people perform yoga on the bank of the river amidst heavy fog on a cold winter morning in Narayanganj, Bangladesh on December 9, 2020. (Photo by Mushfiqul Alam/NurPhoto via Getty Images)

Fire blows from a fogging machine as a worker sprays fumigation vapour to stem the spread of dengue virus along a street in Peshawar, Pakistan, October 18, 2021. (Photo by Fayaz Aziz/Reuters)