As you approach the Children's Museum, look for the 40-foot-high red-and-white milk bottle out front -- and for children and their chronological-adult companions racing each other to the entrance. The under-11 set is the target audience for this delightful museum, but it appeals to the little kid in everyone.

The museum reopened in April 2007 after an ambitious expansion project added 23,000 square feet of space and overhauled the 75,000-square-foot interior of the converted wool warehouse. As they explore, beginning in the glass-enclosed lobby, young visitors can stick with their adults or wander on their own, learning, doing, and role-playing. A three-story-high climbing structure, the New Balance Climb, incorporates motor skills and problem-solving. Other favorite hands-on exhibits include physical experiments (such as creating giant soap bubbles) in Science Playground; Johnny's Workbench, a souped-up version of puttering in the garage; and Boats Afloat, which has a replica of the bridge of a working boat and an 800-gallon play tank modeled after the Fort Point Channel, in front of the museum. You can explore Airplay, which reveals scientific principles using fans, pinwheels, and musical instruments; Boston Black, which celebrates Boston's black history and culture; and the Japanese House, a 2-story replica of a residence in Kyoto (Boston's sister city). Children under 4 and their caregivers have a special room, Playspace, that's packed with toys and activities.

Check ahead for information about traveling exhibitions -- public-TV characters often drop by -- and special programs. And be sure to check out the excellent gift shop (as if you have a choice).