When visiting Chicago, the famous landmarks, museums, fancy shops and culinary scene could keep you completely engrossed for weeks on end. But if you've only got a few days—and you're the adventurous sort—head off the beaten path to discover the secrets that make this city truly enchanting.

Old-Time Speakeasy Secrets

Prohibition was supposed to stop the production and sale of alcoholic beverages. But in Chicago, the law banning liquor seemed to have the opposite effect, at least for those in the know about secret speakeasies. Today you don't have to knock on a back-alley door, give a secret password and sneak into a converted basement bar to enjoy a cocktail. With some help from our Chicago travel guide, you can get a peek into the speakeasy scene of the Roaring 20s at the Drifter, which is a hidden room in Chicago's oldest tavern, the Green Door. Take the speakeasy theme one step further with jazz and burlesque performances to accompany your covert cocktails at Bordel.

Oscar Mayer's Grave

Yes, that Oscar Mayer—the one who is best known today for the Oscar Mayer Weinermobile. From his 19th-century Chicago butcher shop, an empire of processed meat products emerged. You can pay graveside homage to Mr. Mayer in Rosehill Cemetery, one of the oldest cemeteries in the city. A self-guided tour map leads you to the graves of other famous Chicagoans at rest among the Victorian statuary and tall, leafy trees. Look for the Civil War Memorials and the Chicago Volunteer Firefighter's Memorial. When you're done wandering, slip across the street to the quaint, cozy Fireside for drinks.

Mysteries of Surgical Science Revealed

You wouldn't expect to find skulls, scalpels and sinister-looking surgical tools in one of Chicago's oldest, most wealthy neighborhoods. But behind the doors of the mansion that houses the International Museum of Surgical Science, that's just the start of it. From paintings of old-fashioned surgical procedures to a plaster cast of Napoleon's actual death mask, you'll get plenty of decorating ideas for your next Halloween party. On the up side, you'll find new gratitude for today's advanced medical technologies, and a look inside an elegant, historic lakefront mansion. Download the museum's app for an interactive, self-guided tour of the eccentric exhibits, plus stories of the opulent residence and the high society family who lived there.

Becoming a Secret Agent

The Secret Agent Supply Co. has a secret beyond its quirky, yet perfectly descriptive name. When you buy fake mustaches or rearview spy sunglasses, the proceeds go to a worthy cause that has pretty much nothing to do with secrets, spies or undercover operations. The money from sales funds creative writing programs for kids from ages 6 to 18 and the teachers who guide and inspire them. The selection of gear, books and apparel isn't huge, but you'll feel good for spending a few bucks here. And the shop gives you a great excuse to visit the hip, artsy Wicker Park neighborhood. Take a stroll along Milwaukee Avenue to see what's hot and trendy in the boutiques, shops and eateries along the way.

Hidden Park of Oz

Tucked away in a residential area of Chicago's Lincoln Park neighborhood, Oz Park is one of the best kept secrets in Chicago. It's beloved by the community, but rarely seen by visitors who head to nearby, better known Lincoln Park Zoo and the Lake Michigan shoreline. You'll recognize all your favorite characters from the "The Wizard of Oz" in life-size statues scattered throughout the park. Bring the kids—even if they're too young to recognize Dorothy, Toto and the Scarecrow, they can swing, jump and climb on the playground equipment and run on the grassy lawn. When you're ready to rest, head to the Emerald City Garden, a quiet corner of the park surrounded by flower gardens and trees.

Start a New Year With a Search

If you’re in Chicago to watch the New Year’s Eve rising star, you can start actual New Year’s day with an equally fun and interesting event. While planning your trip to the, “Windy City,” look into the Car Rally Scavenger Hunt. Who knew that one of the city’s most popular attractions, Chicago’s Adler Planetarium, would host one of the city’s most secret rallies? The Car Rally Scavenger Hunt is an annual search for Chicago’s most arcane things and places. If you truly want to find Chicago’s hidden gems, what better way than to hop in the car with a friend and scour the city for ordinary, yet extraordinary finds, like extinct breweries or a Polish postage stamp. Discover everything from hamburgers to terracotta architecture and everything in between.