Qwest Tower, Denver

1801 California Street, also known as the Qwest Tower, is a prominent skyscraper located in Denver. Completed in 1983, the building stands at 709 feet (216 meters) and features 52 floors, making it the second-tallest building in both Denver and the state of Colorado. Nationally, it ranks as the 111th-tallest building in the United States.

Originally occupied by the offices of US West, 1801 California Street is now the world headquarters of Qwest Communications. Upon its completion, the building was the tallest in Denver, but it held this title for less than a year before being surpassed by Republic Plaza in 1984.

Architecturally, the Qwest Tower is an example of late-modernist high-rise design. It has a brown concrete façade and features a stepped design with four setbacks. The structure is characterized by its unique shape, resembling two interlocked octagonal sections that diverge near the roof. Atop the building, an antenna mast extends its total height to 738 feet (225 meters), which technically makes it the tallest building in Denver when measured by pinnacle height, surpassing the 717-foot (219-meter) roof of Republic Plaza.

The Qwest Tower remains a significant feature of Denver's skyline, embodying both the architectural trends of the late 20th century and the city's growth as a hub for telecommunications.