Bob Cassilly’s City Museum at St. Louis is Alice-in-Wonderland, down-the-rabbit-hole surreal, going against the logical patterns and enforced pauses that define the ordered grid of a city.

The sound of children playing is the first thing you hear as you approach the gates, painting the air with the joy of play. But it’s misleading: The grown-ups who belong to them (and the ones who don’t) are at play, too. They traverse cage-like ladders to get to airplanes atop metal structures and meander across walkways and ramps built four stories in the air.

This is City Museum in downtown St. Louis, where anarchy is – sometimes quite literally – in the air.

Here, the rules that govern the city and its inhabitants are stripped away. The layout and structure itself is as if Dalí and Gaudí dropped acid in a salvage yard and miraculously managed to create a structure. There is only one directional sign at the front entrance, and the staffers at the ticket counter will tell you quite firmly that there are no maps.

If you gave Dr. Seuss and M.C. Escher free reign over an old shoe factory and told them to build the world’s craziest jungle gym, you’d get the City Museum in St. Louis Missouri.

This isn’t your typical museum. Very little is “for display only,” in fact touching is highly encouraged. The environment you interact with itself is the museum. You climb, crawl, scoot, slide, and ride all the exhibits.

It’s something you may not have ever noticed: a hippo sitting high atop Washington Avenue! But Emily Dittmer did, and she wonders about it every time she walks by.

City Museum is a museum, consisting largely of repurposed architectural and industrial objects, housed in the former International Shoe building in the Washington Avenue Loft District of St. Louis, Missouri. Popular among residents and tourists, the museum bills itself as an “eclectic mixture of children’s playground, funhouse, surrealistic pavilion, and architectural marvel.” Visitors are encouraged to feel, touch, climb on, and play in the various exhibits. The museum attracted over 300,000 visitors in 1999 and over 600,000 in 2007. It has been named one of the “great public spaces” by the Project for Public Spaces, and has won other local and international awards as a must-see destination.

Opened in 1998, City Museum consists largely of repurposed architectural and industrial objects and is housed in the former International Shoe building in the Washington Avenue Loft District of St. Louis, Missouri, United States. City Museum was founded by artist Bob Cassilly who unfortunately passed in 2011. The museum is open seven days a week and admission is $10-$12 depending on time of entry. You can find complete visitor information on their website and Facebook page.

Entering the exhibit hall of the new Exploratorium, we’re greeted by a sight that gives us all pause: two water fountains, one standard issue, the other a toilet fitted with a drinking spout. “Eeew,” says my friend Kristine’s 12-year-old daughter, Lyndsey, echoing my inner (creeped-out) reaction. Her 9-year-old brother, though, has a different response. Philip heads straight for the toilet-fountain, flashes a mischievous smile, and takes a good, long drink. It’s the perfect introduction to a place whose mission is to spark creative thinking and force you to cast off preconceptions.

It’s hard to describe St. Louis’s City Museum to people who haven’t been there, but calling it a giant playground is a good place to start. The 600,000 square foot building, formerly home to the International Shoe Factory, was purchased in 1995 by Bob Cassilly (who died last year while creating a new, similarly whimsical tourist attraction, Cementland). The classically-trained sculptor set out to make a funhouse for young and old out of unique, reclaimed objects found within the city’s municipal borders. Today, the museum accepts things from all over. “As we have grown we have had greater opportunities presented to us of stuff from outside St. Louis,” says museum director Rick Erwin III. “If you have something cool you want to give us, I’m not going to say no just because it’s not from St. Louis. Cool stuff is cool stuff.”

The museum space is based on repetition, solid lines, curves, and colors. “People will call and say, ‘Hey, do you want a vacuum cleaner?’” Erwin says. “I’ll say, ‘No. Do you have a thousand vacuum cleaners? I’ll take that. I want a lot of stuff!’” They hate dead ends and columns and built a full-scale bowhead whale for their first floor. Because the museum is constantly finding things and accepting donations, the space is always growing and changing. The newest space is a series of tunnels underneath the building, a giant indoor treehouse, and a slide that goes into the museum’s pump room. Erwin calls it “The Fungeon.”

The collection includes cranes, old bridges, a human-sized hamster wheel, vintage opera posters, a room of preserved insects, a bank vault, a fish tank full of turtles (and one very friendly 39-pound catfish), and at least one alien dressed like Elvis in a coffin—all accessible via stairs, elevator, tunnel, or slide. (The museum also houses an aquarium and an old-fashioned shoelace-making facility.) “It was all Bob’s idea,” Erwin says. “People think I made him up.” A sign outside reads: “The City Museum is full of creativity, adventure, and learning … and is fraught with DANGER. Enter at your own risk!”

So basically, it’s the coolest—and most entertaining—place on Earth. Here are just 11 of the many awesome things you’ll find at the City Museum.

1. THE 10-STORY SLIDE 
   The International Shoe Company didn’t have freight elevators, so workers sent shoes to different floors on chutes. “Workers would stop the shoes when they saw their size, switch shoes and then send their old shoes down,” Erwin says. Cassilly and company converted the chutes into a dizzyingly fun spiral slide that deposits visitors in the museum’s caves. (There’s also a 5-story slide.)
2. TWO PLANES 
   “The story goes that we purchased them after the flood of 1993,” Erwin says. “One of them belonged to Wayne Newton.” Now, the planes are part of the museum’s MonstroCity; visitors can crawl through a series of wire tubes and explore the interior of the planes.
3. BIG ELI 
   This 30-foot-high Ferris wheel, which was manufactured in 1940, was found in a barn. “It used to be on a flatbed, so it’s actually safer up here,” Erwin says. Before it was put on the roof, it was fully restored.
4. A SCHOOL BUS 
   To create the museum’s exhibits, a team of artisans will often cut through the building’s floors or hoist objects up the side of the building—sometimes without permits, as they did with this school bus, donated by the Roxana School District, that overhangs the roof. “You can actually make it bounce,” Erwin says. “It’s on hydraulics. We spent a lot of money proving that it’s safe.” Also on top of the building: a giant praying mantis sculpture created by Cassilly; a pair of Beluga whale sculptures placed to look like they’re swimming; a dome with a rope swing; and a splash pond. (There were plans to put a water park on the roof—including a slide down the side of the building—but unfortunately the building couldn’t support the weight of the water.) Everything is constructed by the in-house team.
5. THE WORLD’S LARGEST PENCIL …
   This 76-plus foot, 21,500 pound No. 2 pencil was made and donated by Ashrita Furman, who is currently the world record holder of the most world records. It contains 4000 pounds of graphite and is the equivalent of 1,900,000 regular pencils. If you could lift it, you could write with it—and its 250-pound rubber eraser can do its job, too. “It took a crane to get this into the building,” Erwin says. “It was in two pieces.”
6. … AND THE LARGEST PAIR OF UNDERPANTS 
   These 7-foot-tall tighty-whiteys once went missing from the museum’s walls. “They just disappeared one day,” Erwin says. “We vowed that we would go commando until they showed up.” They reappeared 3.5 weeks later, freshly laundered.
7. FIBERGLASS 
   Those things that look like icicles hanging from the City’s first-floor ceiling? It’s actually fiberglass donated by Boeing. “It’s the same stuff you wrap around the outside of an airplane,” Erwin says.
8. COOLING TUBE 
   This cooling tube, located on the museums’s first floor, came from St. Louis-based brewery Anheuser-Busch. “It used to be inside the beer [tank], to keep the beer cold,” Erwin says. Now, visitors can climb up it to other floors of the museum.
9. THE PUKING PIG 
   This is a boiler expansion tank, with the face of a pig, that’s bolted to the back end of a 1899 fire truck. Every 90 seconds, the tank fills with water and tips—which makes the pig look like it’s puking.
10. PIPE ORGAN 
    This organ was built in 1924 for the Rivoli Theater in New York City. It’s been fully restored and is now operated with an electronic console.
11. CROSS 
    This cross came from the east wing of the Alexian Brothers Hospital in St. Louis. That’s where, in the 1940s, the exorcism that inspired the novel and film The Exorcist took place. “The story goes that during the exorcism, the cross was struck by lightning,” Erwin says. “This became very famous in the last year or so. People want to sleep under it. It’s a little weird.”

BONUS! STUFF THEY HAVE THAT’S NOT ON DISPLAY … YET.

The Museum is constantly expanding and tweaking its space as it gets new stuff. Currently, the world’s largest tennis racket—also built by Furman, it measures 50 feet, 3.01 inches long by 16 feet, 8.6 inches wide—is sitting in storage, just waiting for a place in the museum. And there’s more: Various cast iron store fronts from St. Louis, thousands of glass bottles, 50,000 paver bricks, a merry-go-round, an airplane, neon signs, corbels from Chicago Union Passenger Depot, and, says Erwin, “so much terra cotta that we could build an addition.”

Have you been to the City Museum? If so, what’s your favorite part? What cool treasures did we leave out?