A B-52 bomber is watched by a group of curious onlookers as it lands at RAF Fairford, February 21, 1999. The B52s arrived from the U.S.A. as part of NATO's preparations for air attacks on Yugoslavia as tensions in the Kosovo crisis increased. (Photo by Dylan Martinez/Reuters)

Belgium's Crown Princess Elisabeth poses with dancers and youth after a ceremony on the occasion of her 18th birthday, outside the Royal Palace in Brussels, Belgium on October 25, 2019. (Photo by Yves Herman/Reuters)

A member of the Revolutionary Armed Forces of Colombia (FARC) pose for a picture at a camp in the Colombian mountains on February 2005. (Photo by Frank Piasecki Poulsen)

An Extinction Rebellion environmental activist couple getting married at an action site they are calling “The Beacon” on Westminster Bridge on October 7, 2019 in London, England. Primarily made up of London based activists the site is one of 12 situated around key Government locations in central London as actions are also predicted to occur in unto 70 cities around the world. The group aim to occupy the areas in central London for up to two weeks through non violent protest with an estimated 8 times as many people as their April protests which saw over 1,200 people arrested. (Photo by Ollie Millington/Getty Images)

Costumed revelers pose in front of the Chapell bridge on the opening day of the carnival in Lucerne, Switzerland, 20 February 20​20. The carnival takes place in Lucerne from 20 to 25 February 2020. (Photo by Alexandra Wey/EPA/EFE)

Rebel fighters from the Jaish al- Fatah (or Army of Conquest) brigades manoeuver an alleged explosive- rigged make- shift armoured vehicle during a major assault on Syrian government forces West of Aleppo city on October 28, 2016 Syrian opposition fighters launched a major assault on government forces to break a months- long siege of rebel- held neighbourhoods of the battered city of Aleppo. Rebel groups including the powerful Ahrar al- Sham faction and former Al- Qaeda affiliate Fateh al- Sham Front fired waves of rockets into government- held western Aleppo, killing at least 15 civilians, a monitor said. (Photo by Omar Haj Kadour/AFP Photo)

Humanoid robot bartender “Carl” interacts with guests at the Robots Bar and Lounge in the eastern German town of Ilmenau, July 26, 2013. “Carl”, developed and built by mechatronics engineer Ben Schaefer who runs a company for humanoid robots, prepares spirits for the mixing of cocktails and is able to interact with customers in small conversations. (Photo by Fabrizio Bensch/Reuters)

American Paralympic snowboarder Amy Purdy dances with a robot during the opening ceremony of the Rio 2016 Paralympic Games at the Maracana stadium in Rio de Janeiro on September 7, 2016. (Photo by Yasuyoshi Chiba/AFP Photo)