St. Louis ? You’ve been to this city before. You’ve been to the Gateway Arch, the Zoo and Busch Stadium.

You think you’ve done St. Louis?

The City Museum in St. Louis is a constantly evolving work, part playground and part hands-on art show. The newest attraction is called MonstroCity, a bizarre, industrial-size jungle gym made of giant slinky toys and old airplanes.

Not necessarily.

Just ask Steven Fitzpatrick Smith. The 29-year-old has become an activist of sorts for his adopted home. Supported by the civic group Metropolis, which is devoted to all things city, Smith and some friends have launched a television ad campaign called “This is St. Louis.”

The public service spots are aimed at showing off the hidden treasures of St. Louis the places not usually mentioned in the media or well-known to visitors. And Smith, one of the seemingly few St. Louisans who grew up here without developing an inferiority complex about the city, knows more than a few of the treasures.

His first suggestion: The City Museum.

A former downtown shoe factory, The City Museum has become the constantly evolving artwork of owner Bob Cassily. It’s essentially a three-story monument to unbridled creativity two parts playground, one part hands-on art show.

It’s newest attraction is called MonstroCity, a bizarre, industrial-size jungle gym made of giant Slinky toys and old airplanes, among other things. Like the colorful network of slides and tunnels inside the museum, both children and adults are encouraged to climb around.

MonstroCity is hard to describe, but Smith does as good a job as anyone: “It’s like something from Beyond Thunderdome,” Smith said. “It’s just pure insanity. It looks like Bob Cassily’s mind just exploded and became reality.”

One of the “This is St. Louis” spots features a favorite haunt of locals, the Soulard Farmers Market. Since 1838, commerce at its most basic level has been taking place at the market in the historic Soulard neighborhood, where the oldest of its red-brick buildings dates to 1810.

Sandy Hess, left, of Cape Girardeau, Mo., shops for vegetables at Soulard Farmers Market. The market, which offers fruits, vegetables and flowers, has been in existence since 1838 and is a favorite haunt for locals. The owner of the stand, Patricia Randazzo, talks on the telephone at right.

The best day to go is Saturday, when thousands of consumers converge on the market to shop for fresh meat and produce at prices competitive with any grocery store.

“You can buy anything from live chickens … to fresh Amish jams and jellies,” Smith said. “There’s even a pet store, herbs and flowers. It’s very much a distinct flavor of St. Louis.”

But perhaps the city’s best known distinction comes from the sporting life: Widely regarded as one of the country’s most enthusiastic baseball towns, St. Louis is also home to the International Bowling Museum and Hall of Fame.

Located across the street from Busch Stadium, the museum offers a three-story Mecca for lovers of the tenpins. But for an equally historic lesson on bowling, try the Saratoga Lanes in suburban Maplewood, which claims to be the oldest west of the Mississippi River.

The Saratoga slogan: “Eight lanes upstairs since 1916.” Indeed: There are only eight lanes in the small, second-floor establishment and it has been in operation continuously for 86 years.

There aren’t too many alleys left where the same guy hands out the shoes, the drinks and repairs the lanes. Asked to describe the charm of the place, owner Jim Barton says that for some reason, Saratoga always draws the friendliest clientele.

Lee Sherman was among the bowling alley’s frequent visitors when he was a student at Washington University in St. Louis. The 22-year-old has since moved back to his hometown of Queens, N.Y.

But on a recent Saturday night, Sherman made sure to go to Saratoga while visiting his college town. Just before closing time, with Patsy Cline serenading from the jukebox, Sherman described its appeal.

“It’s more of a dive,” Sherman said. “It’s just atmosphere. This is what feels very much like what St. Louis is: It’s kind of cheap, but at the same time, it’s got a lot of character.”

Huge bowling pins hang above the information desk and gift shop at the entrance to the Bowling Hall of Fame. The museum is located across the street from Busch Stadium, home of the St. Louis Cardinals baseball team.