London has unveiled The Orbit, the sculpture at the heart of the Olympic Park, with the city's mayor claiming the bright red swirling structure -- likened by many to a rollercoaster -- is better than the Eiffel Tower.
Boris Johnson said the Anish Kapoor and Cecil Balmond-designed structure, which rises up next to the Olympic Stadium at Stratford in the city's East End was "a masterpiece of design and engineering."
"It endlessly repays the viewer, it is a very rewarding thing to look at. The Eiffel Tower is very simple, the Shard, behind me, is a piece of cake -- any child of two could do that -- this is much more elaborate, more sophisticated, more intriguing and complex," he told CNN.
The tower stands 114.5m tall, making it Britain's biggest sculpture, more than twice the height of Nelson's Column, almost six times the height of the Angel of the North, and 22m taller than the Statue of Liberty.
Watch London's Olympic tower rise
Visitors will climb 455 steps -- or ride one of two elevators -- to two observation decks offering expansive views across London.
Johnson and Lakshmi Mittal, CEO of steelmaker ArcelorMittal, joined forces to champion the creation of a large-scale sculpture at the Olympic Park -- after meeting in a cloakroom at Davos.
"It started as a small project, a casual discussion." Mittal told CNN. "It was just a scribble on a piece of paper. But it expanded and expanded into this exciting project."
Mittal's company stumped up more than £19 million ($30 million) of the £24 million cost of the structure, providing steel from their plants across the globe.
"The Olympics are a global games -- the whole world participates, 202 countries. ArcelorMittal has businesses in so many countries around the world and so I wanted every one to participate," he said.
Kapoor and Balmond won a competition to design the piece, and have watched it rise from the one-time wasteland, as the Olympic venues around it have also taken shape.
Kapoor said the initial brief called for a tower on the Olympic site, "100 meters tall, or more, and we've done more," explaining that the work "questions the concept of what towers can be."
"As you walk up, around and through it, it's as if the object is happening around you," he said, adding that the Orbit "demands, requires, needs public participation."
The artist conceded that the £15 entry fee (£7 for children) was high, but that it had been an expensive project, and that he hoped it would eventually be free, allowing more people to visit