The proposal changed as it developed
Calatrava’s archived account describes an early scheme with a roof around 444 metres and a spire reaching approximately 610 metres. Thornton Tomasetti’s 2007 account discusses the later 2,000-foot residential tower and records construction beginning that year. Those are different design stages; their floor plans and height categories should not be combined into one specification. [1][2]
Why construction stopped
Axios reports that funding dried up during the 2008 recession, leaving the excavation unfinished. Its June 2024 account documents a replacement development by Related Midwest at 400 North Lake Shore Drive. Redevelopment of the land is not a restart of Calatrava’s original tower. [3]
What the engineering record tells us
Thornton Tomasetti describes its role as structural engineer of record working with Calatrava. Its 2007 account treats the narrow site and long vertical circulation as design challenges. It is evidence of an active design and construction programme at that time, not proof that the proposed structure was completed or its operating performance demonstrated. [2]
The lesson: a foundation is not a completed project
Editorial analysis: Early ground works can make a project look inevitable. Delivery still depends on a financed superstructure contract, a viable sales or leasing programme and a sequence that can survive delays. Reusing a site can require substantial redesign even when excavation has already occurred. The distinction between a cancelled tower and its replacement matters in both construction timelines and height rankings.
Read the evidence
[1] Calatrava: original Chicago Spire design ↗
[2] Thornton Tomasetti: 2007 design and construction account ↗