May 25, 1952: This unusual spiral staircase served the Carnegie Building, the headquarters of the Carnegie Steel Co. When completed in 1895, the Carnegie Building was the tallest office building in Pittsburgh, standing at 13 stories or about 200 feet. It was the first steel-framed skyscraper constructed in the city. The building, which had been located at 428 Fifth Ave., was demolished in 1952 — the year this photograph was taken — to allow for the expansion of what today is the Downtown Macy’s store.
(Post-Gazette Photo)