Preparing for digging the basement of the Chicago Spire

At first I thought these walls were the beginning of the structure of the Chicago Spire, but a construction worker told me that these are just the walls to prepare for the monster hole they are digging. The hole is gonna be five stories deep. These metal walls are to prevent the dirt hole from collapsing in on the workers while they work.

I like how you can see the Trump Tower in the background being built. Two monster skyscrapers being built at the same time in Chicago. Both along the Chicago River.

Higher-resolution print available at: www.deviantart.com/print/2032874

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About the spire:
North America's tallest building will be the Chicago Spire towering in a 2,000 feet. It has prime real estate being located just north of the Chicago River and just east of Lake Shore Drive. It will also be at the forefront of the Chicago skyline as viewed from Lake Michigan. Designed by Spanish architect Santiago Calatrava, this skyscraper is scheduled to be completed in 2010 with 150 floors