The giant metal structure sits 330ft above the ground on the roof of a 22 storey office block in Dutch capital Amsterdam on September 6, 2016. Tourists sit in a playground-style chair as they propel themselves them over the edge of the building with only thin-air between them and the ground below. Engineers spent several years designing and building the breathtaking swing. By being fixed to the top of a building it reaches new heights – dwarfing other swings around Europe but trailing behind the 1,150ft high mechanical rides at the Stratosphere Hotel in Las Vegas, Nevada. (Photo by Huub Zeeman/SWNS.com)

A boy rides on a snow wagon towed by a robot dressed as a Teddy bear, which only moves forward by moving its legs, during the Ice and snow carnival at Taoranting park in Beijing February 9, 2015. (Photo by Kim Kyung-Hoon/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)

Thousands of revelers continue to enjoy themselves throughout the night on Sunrise Beach on February 25, 2005 in Haadrian, Koh Phangan. (Photo by Shaul Schwarz/Getty Images)

Iranian girls wearing face masks walk in Tehran, Iran, 02 November 2020. According to the Iranian Health ministry, Iran reported its highest daily COVID-19 death toll and infections by announcing 440 deaths and 8,289 new infections in past 24 hours in what appears to be a third wave of COVID-19 outbreak. (Photo by Abedin Taherkenareh/EPA/EFE)

Participants approach a law enforcement officer with open arms during an opposition demonstration to protest against police violence and to reject the presidential election results near the Government House in Independence Square in Minsk, Belarus on August 14, 2020. (Photo by Vasily Fedosenko/Reuters)

A couple takes selfie pictures amid heart shaped decorations setted for Valentine's day, in Bangkok, Thailand on February 14, 2021. (Photo by Mladen Antonov/AFP Photo)

People walk as snow falls in a main street in Jerusalem, 17 February 2021. Israeli Forecasters and the Meteorological Service ex​pect snow fall in Jerusalem. (Photo by Abir Sultan/EPA/EFE)