An enduring symbol of Chicago and one of the city’s most recognizable buildings, the Wrigley Building is a gleaming terra-cotta structure located at the northwest corner of Michigan Avenue and the Chicago River. The twenty-four story original building (1921) and massive sixteen- story north annex (1924) that comprise the Wrigley Building were constructed to serve as the headquarters of the Chicago-based Wrigley Company, the largest producer of chewing gum products in the world. William Wrigley, Jr. commissioned the architectural firm of Graham, Anderson, Probst and White to design a building that would serve as a fitting monument to the company’s success. The firm drew on a variety of influences ranging from European classicism to early skyscraper development. The resulting structure served as the centerpiece of the new “Gateway to Chicago” created by the opening of the Michigan Avenue Bridge in 1920. As the first major commercial structure constructed north of the river, the Wrigley Building inaugurated the rapid commercial development of North Michigan Avenue during the first half of the twentieth century.