The Woolworth Building, designed by architect Cass Gilbert in 1913, is one of the oldest skyscrapers in the United States. More than a century after the start of its construction, it remains, at 57 stories, one of the fifty-tallest buildings in the United States as well as one of the twenty-tallest buildings in New York City. Since 1966 it has been a National Historic Landmark, and a New York City landmark since 1983.

The Woolworth Building was constructed in neo-Gothic style by architect Cass Gilbert, who was commissioned by Frank Woolworth in 1910 to design the tallest building in the world as the Woolworth Company's new corporate headquarters on Broadway, between Park Place and Barclay Street in Lower Manhattan, opposite City Hall. Originally planned to be 625 feet (191 m) high, the building was eventually elevated to 792 feet (241 m).^{[citation needed]} The construction cost was US$13.5 million and Woolworth paid all of it in cash. On completion, the Woolworth building overtook the Metropolitan Life Insurance Company Tower as the world's-tallest building; it opened on April 24, 1913.

Cass Gilbert (November 24, 1859 – May 17, 1934) was a prominent American architect. An early proponent of skyscrapers in works like the Woolworth Building, Gilbert was also responsible for numerous museums (Saint Louis Art Museum) and libraries (Saint Louis Public Library), state capitol buildings (the Minnesota, Arkansas and West Virginia State Capitols, for example) as well as public architectural icons like the United States Supreme Court building. His public buildings in the Beaux Arts style reflect the optimistic American sense that the nation was heir to Greek democracy, Roman law and Renaissance humanism. Gilbert's achievements were recognized in his lifetime; he served as president of the American Institute of Architects in 1908-09.

Gilbert was a conservative who believed architecture should reflect historic traditions and the established social order. His design of the new Supreme Court building (1935), with its classical lines and small size contrasted sharply with the very large modernist Federal buildings going up along the National Mall in Washington, D.C., which he disliked.