CHICAGO
10/18/2013 01:46 pm ET Updated Oct 18, 2013

Open House Chicago 2013: See The Hidden Treasures Inside Chicago's Most Interesting Buildings

Chicago's stunning and diverse architecture is one of the city's most defining characteristics -- yet the interiors of many of the Windy City's most special structures remain a mystery to even long-time residents.

That all changes for one weekend a year when the doors to many of the Windy City's most magnificent buildings open to the public for the Chicago Architecture Foundation's Open House Chicago.

Though of the spaces are always accessible to the public, others are exclusive clubs or the homes of iconic businesses. Some of the sites which are regularly open for viewing will grant access to little-seen corners -- or observation decks -- for just this weekend. Last year, the event drew more than 40,000 visitors from 56 different countries, every state in the nation and every zip code in Chicago.

The event, which runs Saturday, Oct. 19 and Sunday, Oct. 20, is free and no tickets are required.

We've rounded up just a few of the more than 100 sites stretching from Pullman to West Ridge, the lakeshore and Lawndale (embedded below). The CAF and cooperating sites also provided a special inside look at four of the tour's not-to-be-missed stops: The Fine Arts Building, the Chicago Board of Trade, the Columbia Yacht Club and the Kemper Building (the event's most popular site in 2012).

FINE ARTS BUILDING
Located in the Loop, the Fine Arts Building (or FAB) was once home to the Studebaker Carriage company. Now, artists practice everything from painting to opera inside the historic building that was the studio home to famous tenants like Frank Lloyd Wright. The gorgeous structure also houses one of the last manually-operated elevators in the city.

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Fine Arts Building

CHICAGO BOARD OF TRADE BUILDING
The art deco gem along LaSalle is opening its vault to the public for the first time in more than 80 years -- and this weekend is the only way to get a glimpse at the contents behind a secret door in the vault room.

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Chicago Board Of Trade

COLUMBIA YACHT CLUB
The CYC is the only stop on the open house floating on the water, but visitors can access the normally members-only club docked in Monroe Harbor near downtown. Originally formed for Chicago's 1893 World's Fair, the Columbia Yacht Club has had many homes along the lakeshore over the years. Its current home, the Abegweit, is just one of three floating yacht clubs in the Midwest.

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Columbia Yacht Club

KEMPER BUILDING
Last year's most popular site, OHC visitors flock to what was at one time the city's tallest building to see its unparalleled 360-degree views from the normally-closed 41st floor. This weekend it will be open to the public for just the second time in more than 40 years.

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The Kemper Building

Open House Chicago is Oct. 19-20 around the city. Sites are open rain or shine from 9 a.m. to 5 p.m., some exceptions apply. Divvy Bike rentals are offered at a reduced day rate of $4 by emailing openhouse@divvybikes.com.

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Other Open House Chicago 2013 Sites

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