The deal also is premised on a 120-year ground lease with the Chicago diocese of the Episcopal Church, which is expected to include an option for another 80 years. While the project includes office space for the diocesan offices that will be displaced, the church also will benefit from the income stream provided by the ground lease of the nearly one-acre site at the southwest corner of Huron and Rush streets.

The 330 condominiums would start at the 19th floor. The diocese would occupy the 14th through 18th floors, just above 11 floors of indoor parking. A conference center for the diocese and retail space would be included on the first two floors.

At 775 ft, the height of the building dwarfs most surrounding buildings, including the 37-story Omni Hotel. While new condominium towers built nearby are topping out above the 500- and 600-ft marks, the proposed high-rise next to St. James Cathedral is surpassed by the John Hancock building to the east and the proposed Trump Tower Chicago to the south.

Zoning bonuses increased the maximum size of the building from 505,000 sf to nearly 690,000 sf. Most of the increase was the result of the setback of the upper stories of the building. Green roofs and landscaping also boosted the size of the building, which includes a five-story partially-open void area just below proposed penthouse units, creating a terrace 58 floors above the street. The area might be enclosed with a glass wall after 50th Ward Alderman Bernard Stone, chairman of the city council's committee on buildings.

"I think the wind effect going through that space is a real problem," says Stone, who abstained from voting on the project. "God forbid anyone goes off the side of that building."