Built into the rise of an ancient sand dune -- once the shoreline of Lake Michigan -- Chicago's newest museum bills itself as "an environmental museum for the 21st century." Throughout, the focus is on interactivity, making this a good stop for active kids.

Shaded by huge cottonwoods and maples, the sand-colored exterior with its horizontal lines composed of interlocking trapezoids itself resembles a sand dune. Rooftop-level walkways give strollers a view of birds and other urban wildlife below. Paths wind through gardens planted with native Midwestern wildflowers and grasses, and trace the shore of the newly restored North Pond.

Inside, large windows create a dialogue between the outdoor environment and the indoor exhibits designed to illuminate it. Don't miss the Butterfly Haven, a greenhouse habitat where about 25 Midwestern species of butterflies and moths carry on their complex life cycles (wander through as a riot of color flutters all around you). Another top exhibit is City Science, a 3,000-square-foot, two-story "house" with functional rooms where visitors can view the pipes and ducts that connect our homes with power sources miles away. Water Lab is a model river system demonstrating the uses and abuses that a waterway undergoes as it meanders from rural to urban environments. It's probably safe to say that the Children's Gallery is the only place in town where kids can clamber in and out of a model ground-squirrel town or explore a beaver lodge from the inside.

The sunny Butterfly Cafe offers fresh, healthy meals cafeteria-style. In summer, get there early to enjoy coffee and a muffin -- and the lovely surroundings -- with joggers and other locals.

Allow 1 hour.