The Loop’s Rector building would be designated an official Chicago landmark under a proposal introduced to City Council today by Mayor Brandon Johnson.

Built in 1905 at 79 W. Monroe by restaurateur Charles E. Rector, the 14-story structure is the oldest surviving commercial high-rise designed by Chicago architect Jarvis Hunt. Adorned with classical and modernist Prairie School design elements, the building housed several financial institutions in the 1900s, including Bell Savings & Loan Association, which added the iconic “weather bell” sign to the corner in 1951.

The designation will help protect the building as it undergoes a $64.2 million rehabilitation by R2 Development LLC as part of the City’s LaSalle revitalization initiative. The project will convert 11 floors of vacant offices into 117 mixed-income residential units and retail space.

The designation would protect all exterior elevations, including rooflines, of the building.