The Wrigley Building, constructed by the firm of Graham, Anderson, Probst & White, from 1919-1925, was built initially for United States gum-chewing tycoon, William Wrigley Jr.'s business headquarters. It was the first building of its kind to be housed on Magnificent Mile, pioneering the modern age of industry and architecture. The Building is known for its 250,000 terra-cotta tile exterior and clock tower. The Wrigley Building was Chicago's first air conditioned office building and is now being recreated into a city shopping destination, while serving as offices for various companies.