This architectural beauty was co-created by Louis Sullivan, an American architect best known for coining the phrase “form follows function” and who heavily influenced a young Frank Lloyd Wright. The building is considered the peak of Sullivan’s architectural genius.

The Guaranty Building, now also known as the Prudential Building, was initially completed in 1896 by Sullivan and Dankmar Adler. While most early American skyscrapers borrowed from European aesthetics, Sullivan, who is also known as the “father of the skyscraper,” wanted to create a bold new design that represented the prosperity and momentum of the United States at the end of the 19th century.

Because of his vision, the Guaranty Building’s striking terra cotta facade is adorned with gorgeous, intricate details. Sullivan sought to connect the building to the natural world by creating ornamentation inspired by the spreading branches of a tree at the top of the building. Flowers, seed pods, and writhing green ironwork decorate the lower portions of the structure.

The building was granted National Historical Landmark status in 1975 because of Sullivan’s innovative use of vertical lines, semi-circular arches, and his trademark green ironwork. Today, it’s used as initially intended for general office space, but is also open to the public during regular business hours or by appointment with the Preservation Buffalo Niagara.