The Wrigley Building—the Boul Mich’s two-towered architectural wedding cake that has adorned countless postcards, movie scenes and photos since the 1920s—is scheduled to take a step toward protected landmark status this week, according to an agenda sent to members of the Commission on Chicago Landmarks.

Staff from the Historic Preservation Division of the city’s Department of Housing and Economic Development are set to ask the eight-member commission to confer preliminary landmark status on the internationally-known icon at 410 N. Michigan at the body’s Thursday meeting. A Class L property tax incentive for the Wrigley is also being recommended for approval, the agenda said. Once landmarked, the incentive would provide 12 years of reduced tax assessments for the Wrigley Building’s owners, provided they engage in rehab that equals 50 percent the value of the structure. Wrigley was sold last year for $33 million to a group of investors that included Zeller Realty and the owners of Groupon. The consortium announced plans for an improved plaza and outdoor retail and other fixes to the building. The value of the reduced taxes could be worth millions.

If approved, Wrigley would remain protected from demolition or unsympathetic alterations—such as the metal facade applied to ground level portions at the plaza in 2010—until permanent landmark status is conferred. That the visible and beloved building has escaped city protection had long been a concern of the city’s preservation movement—but it is not alone. Other landmark-quality icons, such as Marina City, the powerful, Riverside Plaza building at 400 W. Madison and Wrigley’s across-the-street neighbor, Tribune Tower have also eluded city landmark protection.

Chewing gum magnate William Wrigley, Jr., built the terra cotta beauty in two stages, finishing with the clock-towered southern building in 1921 and the matching north structure in 1924. The building, designed by the architecture firm of Graham Anderson Probst & White, is impressive by day, but is even more so after sundown when its famously illuminated facade pierces the night. You can see it here in the intro to the late 1950s cop show, M Squad, starring Lee Marvin: