Equitable Building

The Equitable Building, now known as the Commonwealth Building, is a 14-story office building in Portland, Oregon, built between 1944 and 1948. Designed by architect Pietro Belluschi, it originally served as the headquarters of the Equitable Savings and Loan Association. One of the world's first glass-box skyscrapers, it helped define modern architectural elements and predates the famous Lever House in New York. It was the first building to be fully clad in aluminum, fitted with double-glazed windows, and completely sealed and air-conditioned. It is also considered the first major commercial building in the United States to use heat pumps for heating and cooling. Built in the International Style, the tower stands out for its facade of turquoise-green glass. Because of its historical and technical significance, the building was added to the National Register of Historic Places in 1976 and was designated a National Historic Mechanical Engineering Landmark in 1980.