At a cost of at least $50,000 ($344,000 in 2007 dollars), full-size mock-ups of a one-bedroom and efficiency apartment were constructed. Complete with balcony railing, they were furnished by Marshall Field’s department store. Murals were displayed behind the mock-ups, constructed from photographs taken from a helicopter at about where the 40th floor would be later.

The mock-ups were shown to investors and prospective residents.

The two model apartments were open to the public – seven days a week – starting on January 9, 1962. They were located at 316 West Randolph Street, south of the river in the northwest corner of the Loop. This was the office of the rental agent, Marina Management Corporation.

By September 1963, Marina City had furnished model apartments inside the building to show off. The three apartments on the 48th floor of the west tower were designed by members of the Illinois chapter of the American Institute of Interior Designers. The cost to furnish each model apartment ranged from $2,500 to $15,000.

A full size mock-up of an office at Marina City, circa 1963. The “tower” at right is a drawing. This photograph was taken by Bertrand Goldberg perhaps to simulate the view from the fifth floor of the office building, which had not been built yet. The “buildings” in the background are large photographs. Note the Unitrin building, completed in 1962, is shown (immediately left of the tower illustration) still under construction.