A kaleidoscopic array of exhibits in this mammoth structure overlooking the Charles River features cutting-edge, interactive displays that encourage kids and adults to think through thorny scientific problems. More than 600 interactive exhibits include a solar racetrack, a 90ft wave tank, "visible-music" machine, and a mathematics lab. You can play with lightning produced by a generator, or pretend to fly through the cosmos in a model of an American spacecraft. The Charles Hayden Planetarium and Mugar Omni Theater present programs that explore the world of stars, galaxies and phenomena of outer space.