The Glessner House would be the architectural masterpiece in most cities. In Chicago, it’s overshadowed by the legacy of Louis Sullivan, Mies van der Rohe, and Frank Lloyd Wright. Even so, Glessner is a must-see. Built in the 1880s a little south of what is now the Loop, the house and its architect--Henry H. Richardson, who also designed Boston’s famous Trinity Church--had a deep influence on Sullivan and the masters who followed. Public tours are free on Wednesdays and $15 other days. Tickets for more elaborate tours of the home, and of the history-rich neighborhood it’s located in, are available at the Glessner House website. Note that the museum has an active schedule of events, many of them free.