Tuesday morning, the New York City Landmarks Preservation Commission (LPC) announced their decision to designate Philip Johnson and John Burgee’s AT&T Building, now known as 550 Madison Avenue, as a landmark.

The designation protects the exterior of the building, including the facades of the office tower, annex, and enclosed covered passageway, and notably preserving its rose Stony Creek granite cladding and the broken pediment at its crown. Going forward, any proposed alterations to the exterior will require approval and permitting by the LPC.