St. Louis is a children's town, with more than enough to keep them amused, much of it absolutely free (though there is generally a charge for parking). The top-rated St. Louis Zoo, Forest Park (tel. 314/781-0900; www.stlzoo.org), with its Big Cat Country, Fragile Forest for the zoo's great apes, River's Edge with elephants and hippos, Penguin and Puffin Coast, and fascinating Insectarium with everything from giant cockroaches to a butterfly house, is free (fees charged for some attractions, like the animal-contact Children's Zoo). Another freebie is the St. Louis Science Center, 5050 Oakland Ave. (tel. 800/456-7572 or 314/289-4400; www.slsc.org), with full-size, animated dinosaurs and 750 hands-on exhibits covering DNA and genetics, health, aviation, the environment, and more (admission charged for special exhibitions, planetarium, and OMNIMAX Theater). Another free attraction is Grant's Farm, 10501 Gravois (tel. 314/843-1700; www.grantsfarm.com), once farmed by Ulysses S. Grant and now part of the Busch family estate, open mid-April through October and featuring a tram ride through an exotic game preserve, a small zoo, animal shows, a Clydesdale stable, a carriage collection, and a free glass of Anheuser-Busch beer.

Older kids -- and adults -- love the whimsical, one-of-a-kind City Museum, 701 N. 15th St. (tel. 314/231-2489; www.citymuseum.org), created by artists and housed in a former shoe factory. The adventure land features a huge indoor play area filled with imaginative caves, slides, and crawling tubes; a circus performance; train rides; art workshops; a collection of oddities; a funky aquarium; and a five-story outdoor climbing contraption called MonstroCity. With a school bus teetering on its roof, this fun house is like no other. Admission is $12, plus $6 for the aquarium. At the education-oriented Magic House children's museum, 516 S. Kirkwood Rd. (tel. 314/822-8900; www.magichouse.org), children 10 and under have a blast experimenting with magnets, water, and tools; testing their fitness; role-playing in a kid-size village; zooming down a three-story slide; and watching their hair stand on end as they touch an electrically charged ball. Special sections are geared toward younger children and toddlers. Admission is $7.50.

The biggest attraction for kids is the huge amusement park, Six Flags St. Louis, 30 miles west of St. Louis on I-44 (tel. 636/938-4800; www.sixflags.com), with thrill rides such as Xcalibur (a slinging, rotating catapult) and the Evel Knievel Coaster, plus Looney Tunes Town for younger visitors, live entertainment, and even a waterpark with a wave pool, slides, and more. Admission is $45 adults, $30 kids under 48 inches tall; 2 years and younger are free. Discount tickets are often available on the park's website. It's open weekends April, May, September, and October, and daily in summer.

Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.