People look at a man, who residents said was killed by al Qaeda militants, hanging on a bridge in Yemen's southeastern city of Mukalla June 17, 2015. Al Qaeda militants in Yemen killed two alleged Saudi spies, residents said, accusing them of planting tracking devices which enabled the assassination of the group's leader in a suspected U.S. drone strike. (Photo by Reuters/Stringer)

This aerial picture taken on June 6, 2016, shows the scene of a collision between a freight train and a passengers train on their way between Liege and Namur, in Saint-Georges-sur-Meuse, Eastern Belgium. Investigators worked through the wreckage of a high speed train crash in eastern Belgium on Monday that killed at least three people and injured nine others. A fast-moving passenger train late Sunday slammed violently into the back of a slow-moving freight train that was travelling on the same track for reasons that remain unexplained. (Photo by Laurie Dieffembacq/AFP Photo)

Participants of an unauthorized opposition rally gather in Tverskaya street in central Moscow on June 12, 2017. Authorities detained Russian opposition politician Alexei Navalny and hundreds of his supporters on Monday, as they mounted demonstrations across the nation against government corruption. Over 200 were detained in Moscow and Saint Petersburg an hour into the protest, according to an NGO that tracks arrests, with Navalny himself picked up by police in his building as he was headed to the event. (Photo by Vasily Maximov/AFP Photo)

A vendor pushes an improvised cart with a woman and merchandise along a rarely used rail track in Bangkok, Thailand, Thursday, June 25, 2020. Daily life in the capital slowly returns to normal as the Thai government eases many restrictions imposed weeks ago to combat the spread of COVID-19. Though emergency regulations require the use of face masks in public, some residents have become apathetic as Thailand has record zero local transmission for over three weeks. (Photo by Gemunu Amarasinghe/AP Photo)

Senior hurricane forecaster Dr. Jack Beven studies computer models as he tracks Tropical Storm Arlene at the National Hurricane Center on June 29, 2011 in Miami, Florida. Arlene is the first named storm of the 2011 Atlantic hurricane season and is moving at 8 mph, packing sustained winds of 50 mph as it heads towards the east-central coast of Mexico. (Photo by Joe Raedle/Getty Images)

Passengers take photos at a wildfire while traveling on a train in Zamora, Spain, Monday, July 18, 2022. When Francisco Seoane's train unexpectedly stopped in Spanish countryside that was being engulfed by a wildfire, he and other passengers got a fright when they looked out at flames encroaching on both sides of the track. The Spaniard told The Associated Press it was scary to see how quickly the fire spread. Video of the unscheduled – and unnerving – stop shows about a dozen passengers in Seoane's railcar appearing alarmed as they look out of the windows Monday. (Photo by Francisco Seoane Perez/AP Photo)

“A monowheel is a one-wheeled single-track vehicle similar to a unicycle. However, instead of sitting above the wheel, the rider sits either within it or next to it. The wheel is a ring, usually driven by smaller wheels pressing against its inner rim. Most are single-passenger vehicles, though multi-passenger models have been built.

Pedal-powered monowheels were built in the late 19th century; most built in the 20th century have been motorized. Some modern builders refer to these vehicles as monocycles, though that term is also sometimes used to describe motorized unicycles. Today, monowheels are generally built and used for fun and entertainment purposes, though from the 1860s through to the 1930s, they were proposed for use as serious transportation”. – Wikipedia

Photo: Cycle inventor Kerry McLean poses for the photographer 2000 in Walled Lake, Michigan. The “Monocycle” is equipped with a 40-horsepower engine, 4ft tire and is expected to reach speeds upwards of 100 mph. (Photo by Bill Pugliano/Liaison)

Aerobatic pilot Sean D. Tucker flies in the two-seat Oracle Extra airplane over downtown Chicago skyline, Wednesday, June 8, 2016. Tucker will perform before the start of of the America's Cup World Series racing on Saturday and Sunday. (Photo by Kiichiro Sato/AP Photo)