OK, so... from left to right, we have: The Doral, by Reinheimer and Associates (1982) One Prudential Plaza by Naess & Murphy (1955) Two Prudential Plaza by Loebl, Schlossman & Hackl (1990) Standard Oil Building (now Aon Centre) by Edward Durell Stone and Perkins & Will (1970) Aqua by Studio Gang (2007) Blue Cross-Blue Shield Building by Goetsch Partners and Lohan Assocates (1995) Oh, and I think the Pritzker Pavilion in the foreground is by somebody, too, but I can't remember his name...