1546 California and 1555 Welton

A concept plan submitted to the city last week proposes a 673-foot “Spiral Tower” for a surface parking lot in the heart of downtown Denver, potentially making it one of the tallest structures in the state.

Filed June 24 under the name Barry Gilbert, the plan outlines an observation tower just off the 16th Street Mall. If approved and built, it would rise taller than the Wells Fargo Center and just shy of Republic Plaza’s 714-foot peak.

Renderings depict a twisting column capped by a glowing orb or starburst-like form. A small base building, likely for ticketing or support, sits at the edge of the lot, with a surrounding plaza also indicated.

While the visuals are bold, the filing offers little technical detail. Diagrams are sparse, labeled in meters, and provide no info on programming, materials, or public access. The city confirmed no rezoning has been requested, meaning no public hearings are currently planned.

“This is just a concept submittal, so we don’t yet know the full intent behind the structure,” said Chris Gleissner, director of site design and neighborhood development for Denver CPD.

The site is within a designated historic district, meaning the Landmark Preservation Office will be involved. The tower will also face scrutiny under downtown design guidelines, including shadow limits outlined in the Waldron Diagram, meant to protect sunlight along the 16th Street Mall.

DenverInfill first reported the filing. The property appears tied to a family ownership group once associated with the Bank of Denver, now part of MidWestOne Bank.

No architect is listed in the submittal, and attempts to reach the applicant were unsuccessful. A similar 81-story tower was proposed nearby in 2018 but never materialized.