Members of the “Exit Point” amateur rope-jumping group stage a performance as they jump from a 44-metre high (144-ft) waterpipe bridge in the Siberian Taiga area outside Krasnoyarsk, November 3, 2013. Fans of rope-jumping, a kind of extreme sport involving a jump from a high point using an advanced leverage system combining mountaineering and rope safety equipment, marked the end of the group's jumping season and recent Halloween festivities. (Photo by Ilya Naymushin/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)

A long exposure image shows star trails from the abandoned submerged orthodox church of St. Nicholas without roof, submerged in the Mavrovo Lake, near Mavrovi Anovi, North Macedonia, 17 March 2019. Constructed in 1850 and submerged in 1952 due to the construction of the hydro system Mavrovo, the church St. Nicholas continues to attract the attention of almost every visitor as it peaks from the water. (Photo by Georgi Licovski/EPA/EFE)

A cat tries to find dry ground around an apartment complex in Houston after Hurricane Harvey hit on Aug. 30. Harvey made landfall in South Texas on August 25, leading to days of downpours that dumped more than 50 inches of rain. Harvey damaged or destroyed about 200,000 homes as the storm system flooded much of Houston and smaller coastal communities. (Photo by Scott Olson/Getty Images)

A man rides his motorcycle along an empty street in Cali on April 17, 2021, during a curfew imposed by the government to help curb infections of the novel coronavirus, COVID-19, as weekend partial lockdown takes effect in four Colombian cities. In recent weeks, the Colombian government has imposed, and then tightened, a series of restrictions to stem a third wave of infections that is bringing its health system to the brink of collapse. (Photo by Luis Robayo/AFP Photo)

School girls stand next to a ballot box at a polling station during the municipal elections in Havana April 19, 2015. Cuba held its first local elections since a historic thaw in relations with the United States with an unusual wrinkle in the single-party system: two of the 27,000 candidates openly oppose the government. (Photo by Reuters/Stringer)

Revelers gather on a commuter train platform of the HVV city public transportation system to drink alcohol on September 30, 2011 in Hamburg, Germany. Thousands of people participated in the event dubbed the “HVV Abschiedstrinken” (HVV Farewell Drink) that was organized through Facebook and is meant to celebrate the last day before a ban on alcohol consumption goes into effect on the city's public transport. (Photo by Joern Pollex/Getty Images)

These Filipino icons of ingenuity were originally re-crafted from abandoned US army jeeps after the second world war, and helped to establish a new system of urban transportation. Jeepneys are being phased to help ease city congestion, but the move will also cause unemployment for experienced drivers – and higher fares for commuters. (Photo by Claudio Sieber/Barcroft Media)