Seattle Center's 1995 decision to renovate its International Fountain into something you interact with, rather than just look at, was a brilliant one. Any warm day, and even some cool ones, you see kids romping around inside this grandly curved, gently sloped, 200-foot-diameter basin, squealing and running when the water jets in the stainless-steel dome start arcing farther, and screaming and cheering when the water cannons explode 150 feet into the air. It's Seattle's backyard sprinkler, and it and the surrounding lawn make the Center a place to hang out in, rather than somewhere merely to pass through.—Gavin Borchert