Costumed attendees participate in the Dragon Con Parade, during the annual science fiction, pop culture and fantasy convention in Atlanta, Georgia, USA, 02 September 2023. Thousands of attendees, some costumed, crowd downtown Atlanta for the annual Labor Day Weekend gathering. (Photo by Erik S. Lesser/EPA/EFE)

“Contrails (short for “condensation trails”) or vapour trails are artificial clouds that are the visible trails of condensed water vapour made by the exhaust of aircraft engines. As the hot exhaust gases cool in the surrounding air they may precipitate a cloud of microscopic water droplets or, if the air is cold enough, tiny ice crystals”. – Wikipedia

Photo: An airplane leaves a vapor trail as it flies in front of he moon on January 17, 2007 above Hanover, Germany. (Photo by Alexander Hassenstein/Getty Images)

“A fter the former Soviet Union conducted its first nuclear test in August 1949, the US reevaluated its postwar defense policies. With the US monopoly on atomic weapons broken, military and political leaders chose to diversify the American stockpile by developing thermonuclear and tactical nuclear weapons. One of the more interesting concepts to come out of this period was atomic artillery, which was successfully tested at the Nevada Proving Grounds (now the Nevada Test Site) in May 1953”. – Alan Carr. Photo: Atomic Annie at work during the Upshot-Knothole test series, 1953. (Photo by Los Alamos National Laboratory/US Army)

Students hold their weapons before the swearing in ceremony for the military students, in Bucharest, Romania, Wednesday, October 25, 2017. The Romanian Army is proudly celebrating their Army Day and marking 100-years since the landmark battle of Marasesti, a key World War I battle in 1917 when Romanian and Russian soldiers defeated German troops, halting a German offensive. (Photo by Vadim Ghirda/AP Photo)

The Sugar Plum Fairy, Katherine Free, left, dances with the dog, Pig, during the Birmingham's Ballet “Mutt-cracker”, a rendition of the famous ballet “The Nutcracker”, in Birmingham, Alabama, December 8, 2016. (Photo by Brynn Anderson/AP Photo)

A team of female cadets takes part in a tug-of-war competition at Budyonny Military Academy of the Signal Corps in St Petersburg, Russia on March 7, 2021. (Photo by Peter Kovalev/TASS/Profimedia)

A member of the Cuban Red Cross takes a break after working in the rubble at the site of a deadly explosion that destroyed the five-star Hotel Saratoga in Old Havana, Cuba, Monday, May 9, 2022. (Photo by Ramon Espinosa/AP Photo)

A swan sits on her eggs on nest made of rubbish found in the Danube river in Belgrade, Serbia on Monday, May 10, 2022. (Photo by Darko Vojinovic/AP Photo)