A worker prepares the “Cutter Head” of the Port Tunnel boring machine for attachment to the tunneling machine on September 1, 2011 in Miami, Florida. The $45 million machine is longer than a football field and about as tall as a four-story building and it will carve the twin tunnels connecting Watson Island and Dodge Island. The the new $1 billion Port of Miami tunnel is expected to be completed in May of 2014. (Photo by Joe Raedle/Getty Images)

Built for over a million people, the city of Ordos was designed to be the crowning glory of Inner Mongolia. Doomed to incompletion however, this futuristic metropolis now rises empty out of the deserts of northern China. Only 2% of its buildings were ever filled; the rest has largely been left to decay, abandoned mid-construction, earning Ordos the title of China's Ghost City.

Roof-topping enthusiast Daniel Lau takes a selfie with high-rise buildings down below as he stands on the top of a skyscraper in Hong Kong, China on August 15, 2017. A craze that began in Russia has now taken hold in Hong Kong, one of the world's most vertical cities. Mr Lau said he had been inspired by Russian climbers and that he was unafraid of the vertiginous heights he scales. (Photo by ImagineChina/Rex Features/Shutterstock)

“The Eiffel Tower (French: La Tour Eiffel, nickname La dame de fer, the iron lady) is a puddle iron lattice tower located on the Champ de Mars in Paris. Built in 1889, it has become both a global icon of France and one of the most recognizable structures in the world. The tower is the tallest building in Paris and the most-visited paid monument in the world. Named for its designer, engineer Gustave Eiffel, the tower was built as the entrance arch to the 1889 World's Fair. The tower stands 324 metres (1,063 ft) tall, about the same height as an 81-storey building”. – Wikipedia

Photo: French engineer Alexandre Gustave Eiffel (1832–1923), left, poses high on the steps of the completed Eiffel Tower, which he designed for the 1889 Paris Exposition. (Photo by General Photographic Agency/Getty Images)

In this Thursday, May 8, 2014 photo, guests look down from the Tilt!, a new tourist attraction that provides guests a unique view of the downtown area from the 94th floor of the John Hancock Building, after it was unveiled in Chicago. People hold onto handrails as the glass and steel facade tilts forward 30 degrees. (Photo by Ashlee Rezin/AP Photo/Sun-Times Media)

Chinese rescuers carry an injuried resident after an earthquake hit an area of Ludian county in Zhaotong in southwest China's Yunnan province on August 3, 2014. At least 300 people were killed and 1,300 injured after a strong earthquake hit southwest China's mountainous Yunnan province, state media said. The quake in Zhaotong prefecture, in the province's northeast, toppled buildings and left residents frantically searching for survivors beneath the rubble, images on social media showed. (Photo by AFP Photo)

A pro-democracy demonstrator fights with a Soviet soldier on top of a tank parked in front of the Russian Federation building on August 19, 1991, after a coup toppled Soviet President Mikhail Gorbachev. The same day, thousands in Moscow, Leningrad, and other cities answered Russian Republic President Boris Yeltsin's call to raise barricades against tanks and troops. (Dima Tanin/AFP/Getty Images)