Anish Kapoor’s ‘Cloud Gate’ sculpture became an iconic symbol of Chicago in the mid-00’s. Constructed between 2004 and 2006 at Chicago’s Millennium Park its external surfaces reflected the sky (the name referred to it acting as a type of gate that helps bridge the space between the sky and the viewer).
Reddit user anticommander compiled a detailed album of its engineering and construction.
The actual sculpture measured 66’L x 33’W x 42’H and weighed in at 110 tonnes. Each arch is 12′ high and the concave underside, called the omphalos, is 27′ above the ground.