South Korean soldiers participate in a winter river crossing operation in preparation for a possible North Korean attack on February 8, 2012 in Yeoju, South Korea. The Korean peninsula is the world's last Cold War frontier as stalinist North Korea and pro-western South Korea have been technically at war since the 1950-53 conflict. (Photo by Chung Sung-Jun/Getty Images)

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 model in Mongolia costumes prepares backstage in Xiangshawan Desert, also called Sounding Sand Desert on July 18, 2013 in Ordos of Inner Mongolia Autonomous Region, China. Xiangshawan is China's famous tourist resort in the desert. It is located along the middle section of Kubuqi Desert on the south tip of Dalate League under Ordos City. Sliding down from the 110-metre-high, 45-degree sand hill, running a course of 200 metres, the sands produce the sound of automobile engines, a natural phenomenon that nobody can explain. (Photo by Feng Li)

Wang Jiayun, born June 18 1993. Wang’s height is 164cm, her weight 42kg. Wang Jiayun says she was born in Kowloon of Hong Kong Special Administrative Region, and presently lives in Shenzhen City of Guangdong province in China. Identity: High school student. Wang's large eyes, pale face, perfectly structured nose and extremely slim figure resemble a brand of human-sized blow-up doll popular with Korean men. This cute and s*xy barbie doll look a like is hot property. She recently became the No.1 searched name in the country's top search engine, Naver.com. Photo: Wang Jia Yun (王嘉韻 or 왕지아인). (Photo by Wang Jia Yun)

“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)

A robot named “Robovie-II”, developed by Japanese robotics research institution ATR, moves around at a grocery store during a shopping assisting experiment by utilizing the robot in an ubiquitous network technology platform in Kyoto, western Japan January 6, 2010. (Photo by Yuriko Nakao/Reuters)

In this Thursday, February 9, 2017 photo, a Bangladeshi boy pulls a rickshaw loaded with strips of leather at the highly polluted Hazaribagh tannery area in Dhaka, Bangladesh. Hazardous, heavily polluting tanneries with workers as young as 14 supplied leather to companies that make shoes and handbags for Western brands, a nonprofit group that investigates supply chains says. (Photo by A.M. Ahad/AP Photo)

A woman takes selfie as municipal workers use cranes to lift carcass of Bryde whale at the Juhu beach, in Mumbai, India, Friday, January 29, 2016. Marine biologists in India were conducting an autopsy on the carcass of 35-foot long Bryde whale that washed ashore on a popular beach in the western city of Mumbai. The beached mammal which appeared to have died at sea two or three days ago was spotted on the beach Thursday by late evening walkers, who informed police. (Photo by Rajanish Kakade/AP Photo)