Navy Pier
Opened in 1916 as Chicago Municipal Pier, as part of Daniel Burnham's Plan of Chicago, to centralize the harbor operations of Chicago and open up the river and rivermouth. Soon, downtown Chicago lost all of its harbor operations due to trains and trucks, and the better harbor at Lake Calumet 20 miles away.
It's been 'adaptively' reused many times through its history. It was operated by the Navy during WWII to train sailors, which is why it is called "Navy" Pier today; later, the University of Illinois held classes there to educate returning veterans under the GI Bill. It also hosted exhibitions of art, music, and cuisine during this time, as well as concerts.
In 1990, it was renovated into what it is today - a festival marketplace with a whole host of tourism-oriented attractions, from Chicago Childrens' Museum to convention space to the Skyline Stage. Many charter boats, including a tall ship, are moored along the south side of the pier. Recently, the Chicago Shakespeare Theater moved to unused space on the Pier.