452 Fifth Avenue, Office skyscraper on Fifth Avenue, Manhattan, US

452 Fifth Avenue consists of the 30-story, 400-foot HSBC Tower, completed in late 1985 and designed by Attia & Perkins, wrapped around the 10-story Knox Building, a Beaux-Arts structure of 1902 by John H. Duncan. The tower's glass facade curves around the Knox Building's north side; the Knox facade keeps its rusticated limestone, a cornice above the sixth floor and a mansard roof.

The Knox Building was erected in 1901–1902 for Edward M. Knox, who ran the Knox Hat Company and leased upper floors to office tenants; John H. Duncan designed it in the Beaux-Arts style. In 1964 the Knox heirs sold it to founders of the Republic National Bank of New York, which bought neighboring lots in the 1970s and hired Attia & Perkins for a tower wrapping the old building. The 30-story HSBC Tower was completed in late 1985.

The Knox Building takes its name from Edward M. Knox, who ran the Knox Hat Company and had it built in 1901–1902, leasing upper floors to office tenants. The Republic National Bank of New York, founded in 1964 after buying the building, later wrapped its HSBC Tower around the Knox structure. The preserved Beaux-Arts base still shows the original show windows and an iron-and-glass canopy on Fifth Avenue.

The building sits at the corner of Fifth Avenue and 40th Street with clear street-level visibility and access through the modern lobby. Nearby Bryant Park serves as an easy navigation reference and the location connects well to public transportation options.

The tower was planned as one of two symmetrical towers flanking Fifth Avenue to form a gateway to upper Fifth Avenue; the matching tower across the avenue was never built, so only this curved glass facade exists. The Kress Building at the 39th Street corner, built in the mid-1930s in Art Deco style, is also incorporated into the complex but was not given landmark designation.