The Wrigley Building is one of America's most famous office towers and an iconic symbol of Chicago. It is located on Michigan Avenue on the north bank of the Chicago River, at the southernmost point of Chicago's Magnificent Mile. The Wrigley Building consists of two towers connected by two enclosed walkways, one on the third floor and the other on the fourteenth floor. The Wrigley Building was sold in September 2011 by Mars, Inc., to a group of investors led by BDT Capital Partners, which includes Zeller Realty Group. Zeller Realty Group serves as an asset manager, developer, and property manager. Both Zeller Realty Group and Newmark Knight Frank serve as leasing agents for available office space; Stone Real Estate serves as leasing agents for retail space. Zeller Development Corporation led the $70 million renovations of the 90-year old building. Today, the 472,639-RSF building has two new renovated lobbies, elevator cabs, multi-tenant corridors, restrooms, brand-new conference center, windows, HVAC, plumbing, electrical, and sprinkler system. The redevelopment removed various building additions over time, restoring it to the original design along with the transformation.