The construction of The Chicago Spire started in July 2007. Over the following months, 34 supporting caissons will be drilled 120 feet into bedrock below the site, providing the foundation for all subsequent construction. The caisson support system was pioneered in Chicago at the end of the nineteenth century and has been pivotal in creating the city's already impressive skyline. Case Foundation Company, who were engaged in June to commence works, are delighted with progress so far. This sub-ground phase of development will be completed by Q1 2008.