A 20 metre high spiral staircase in a tower used as an emergency exit, is seen inside a Federal Reserve bank (Bundesbank) bunker, prior to the bunker's official opening to the public in Cochem, Germany, March 18, 2016. West Germany's Central Bank (Deutsche Bundesbank) stored some 20 billion German marks of emergency notes in two underground bunkers, one in Frankfurt the other in Cochem, between 1964-1988 during the cold war. (Photo by Kai Pfaffenbach/Reuters)

“The Boeing X-45 unmanned combat air vehicle is a concept demonstrator for a next generation of completely autonomous military aircraft, developed by Boeing's Phantom Works. Manufactured by Boeing Integrated Defense Systems, the X-45 was a part of DARPA's J-UCAS project”. – Wikipedia

Photo: Two X-45A Unmanned Combat Air Vehicles (UCAV) are shown to members of the news media July 11, 2002 at Edwards Air Force Base, California. The X-45A, developed by The Defense Advanced Research Projects Agency and the Boeing Company, is the first unmanned system designed from inception for combat missions. (Photo by David McNew/Getty Images)

Guests have breakfast as another guest climbs to gather at the Skylodge Adventure Suites in the Sacred Valley in Cuzco, Peru, August 14, 2015. Tourists taking on an arduous climb up the steep cliff face of Peru's Sacred Valley are being rewarded for their efforts by being able to spend the night in transparent mountaintop sleeping pods at the “Skylodge Adventure Suites”. To reach the pods, visitors need to climb 400 metres of via ferrata (a steel cable and rungs) up the valley side or hike an intrepid trail through zip lines. (Photo by Pilar Olivares/Reuters)

A male green anole lizard flares his throat fan in a backyard in Cary, North Carolina on April 27, 2021. This pink section is actually a thin flap of skin that hangs down below the green anole's throat. Anoles are renowned for their displays in which they do pushups, bob their heads up and down, and unfurl their colorful dewlaps. The male anole uses it for two primary purposes: to protect his territory and attract a mate. (Photo by Bob Karp/ZUMA Press Wire/Alamy Live News)

A woman walks past murals adorning the walls of Garibaldi subway station, in Milan, Friday, February 28, 2020. Due to the COVID-19 virus outbreak in northern Italy, the bustling metropolis of Milan has resembled more of a ghost town lately, as workers stayed home and tourism has dwindled there, and other parts of Italy. (Photo by Luca Bruno/AP Photo)

Greyhounds compete during a race at Santiago city, March 8, 2014. With over 100 years of history, greyhound racing attracts people mainly from rural areas of Santiago every weekend. Some dogs come from Argentina, the United States and Ireland and can develop a speed of up to 80 kilometers per hour on a straight running track of about 200 meters, according to organisers. Bets range from $2 to $1,000 per race, offering a livelihood for breeders and gamblers. (Photo by Ivan Alvarado/Reuters)

Dublin student beat depression by befriending sharks, stingrays and pigs in the Bahamas. Awesome underwater pictures show the 23-year-old diver cosying up to a range of animals including turtles, stingray and sharks. The sunny selfies were taken in the Bahamas by Stuart’s Cove dive instructor and native of the island, Amelia Klonaris – who beat depression by embracing her incredible beach paradise lifestyle. (Photo by Amelia Klonaris/Mediadrumworld)

The Lexus UX concept is displayed on media day at the Paris auto show, in Paris, France, September 30, 2016. (Photo by Benoit Tessier/Reuters)