399 Park Avenue

 office building, bank, skyscraper, International style architecture

524-foot, 41-story International-style office building completed in 1961. Designed by Carson Lundin & Shaw and Kahn & Jacobs, it was built as the World Headquarters for Citigroup, who remained here until 2015, when they moved to 388 Greenwich Street. 399 Park Avenue occupies the full block, and is clad in metal and light-blue tinted glass, with four panes separated by aluminum mullions in each bay, which are in turn separated by grey steel piers. Between each pier, dark-grey metal spandrels divide the floors.

The west and east facades span eight bays; on the west facade fronting Park Avenue the north bay and the three south bays are set back the width of one bay as 6-story low-rise wings. The two bays next to the southernmost then extend to the 11th floor before setting back to the lower roof line, from which the main tower slab rises at the west half of the lot, oriented east-west. At the 6-story base, the long north and south facades span 16 bays (plus the extra bay at the west end where the tower projects forward). There is a small setback at the east end, with the 7th-12th floors spanning 17 bays, and then the main tower slab at the west continuing up vertically with the western 10 bays. The east and west sides of the upper tower span four bays. The top three levels have mechanical floors with black metal vents.

The ground floor is recessed, with plate-glass storefronts, and glass-walled entries at the middle bays on Park Avenue. There are also secondary entrance at the middle of the north and south facades, both deeply-recessed with glass doors atop low sets of steps. Three of the middle bays on the east facade on Lexington Avenue (corresponding to the projecting entrance bays on Park Avenue) are deeply recessed and have additional glass doors at the center, with stainless-steel facing on either side.

The ground floor is occupied by a Dishes restaurant, a Citibank branch, CVS pharmacy, Shake Shack, and Beatnic Vegan restaurant. Along the middle of the north facade on 54th there are seven loading docks and two bays with metal service doors.