Tribune Tower Addition

The Tribune Tower Addition, also known as Tribune East Tower, is a proposed mixed-use supertall on the east side of the Tribune Tower property at 421 North Michigan Avenue in Chicago's Streeterville neighborhood, on the land between the landmark neo-Gothic tower and Lake Shore Drive, a 102-story tower with 564 residences and 250 hotel keys.

Designed by Chicago firm Adrian Smith + Gordon Gill Architecture for developers CIM Group and Golub & Company, the tapering tower would rise roughly 1,400 feet beside the 1925 landmark - several times its height - and would rank among the tallest buildings in the United States. The program pairs 564 luxury residences with hotel keys, ground-floor retail and structured parking, extending the Tribune Tower's own conversion from newspaper headquarters into condominiums into a full two-building Michigan Avenue complex. Its estimated cost tops $1 billion, and its slender, faceted form was shaped in part to preserve views of and around the historic tower on one of Chicago's most visible riverfront corners.