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 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)

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)

Russian support personnel work to help get Expedition 29 crew members out of the Soyuz TMA-02M spacecraft shortly after the capsule landed with Expedition 29 Commander Mike Fossum, and Flight Engineers Sergei Volkov and Satoshi Furukawa on November 22, 2011 outside of the town of Arkalyk, Kazakhstan. NASA Astronaut Fossum, Russian Cosmonaut Volkov and JAXA (Japan Aerospace Exploration Agency) Astronaut Furukawa are returning from more than five months onboard the International Space Station (ISS) where they served as members of the Expedition 28 and 29 crews. (Photo by Bill Ingalls/NASA via Getty Images)

President Barack Obama watches as Joey Hudy (L), 14, from Phoenix, Arizona pumps the Extreme Marshmallow Cannon he invented, while touring student science fair projects on exhibit in the State Dining Room at the White House February 7, 2012 in Washington, DC. Obama hosted the second White House Science Fair celebrating the student winners of science, technology, engineering and math (STEM) competitions from across the country. (Photo by Molly Riley-Pool/Getty Images)

“Space Exploration Technologies Corp. (SpaceX) is an American space transport company founded by PayPal co-founder Elon Musk. It has developed the Falcon 1 and Falcon 9 rockets, both of which are built with a goal of being reusable launch vehicles. SpaceX is also developing the Dragon spacecraft to be carried to orbit by Falcon 9 launch vehicles. SpaceX designs, tests and fabricates the majority of their components in-house, including the Merlin, Kestrel, and Draco rocket engines. In December 2010, SpaceX became the first private company to successfully launch, orbit and recover a spacecraft (a Dragon)”. – Wikipedia

Photo: Elon Musk, CEO of Space Exploration Technologies Corp, speaks during a news conference at the National Press Club April 5, 2011 in Washington, DC. Elon Musk, CEO of Space Exploration Technologies Corp (SpaceX) and Tesla Motors, held the news conference to announce SpaceX's Falcon Heavy rocket which could complete missions to the International Space Station and Moon and should be ready for use by the end of 2012. (Photo by Brendan Smialowski/Getty Images)

“SpaceShipOne was a suborbital air-launched spaceplane that completed the first manned private spaceflight in 2004. That same year, it won the US$10 million Ansari X Prize and was immediately retired from active service. Its mothership was named “White Knight”. Both craft were developed and flown by Mojave Aerospace Ventures, which was a joint venture between Paul Allen and Scaled Composites, Burt Rutan's aviation company. Allen provided the funding of approximately US$25 million”. – Wikipedia

Photo: A chase plane follows SpaceShipOne after it reached a height of 62 miles in the first non-governmental flight to leave the Earth's atmosphere on June 21, 2004 in Mojave, California. SpaceShipOne spacecraft was carried to a height of 50,000 by the twin-turbojet high-altitude research aircraft, “White Knight”, where it was launched for its final climb. The space effort was funded by Microsoft co-founder Paul Allen and headed by aerospace engineer Burt Rutan. (Photo by Jim Campbell-Pool/Getty Images)

A replica model of a Lamborghini Aventador LP 700-4 in Dubai, UAE. This is the world's most expensive model car, made from carbon fibre and covered in a thin layer of pure gold. The 1:8 scale replica Lamborghini Aventador LP 700-4, designed by German engineer Robert Gülpen, is available to buy for £200,000. But amazingly this model – currently on display at the Lamborghini showroom in Dubai – is just a prototype for a solid gold model, which will go up for auction in 2014 with a price tag of £4.6 million. (Photo by Robert Gulpen/Barcroft Media)