Six Flags White Water is the Atlanta area's big summer water park, close enough to Marietta to work as an easy half-day escape when the Georgia heat gets heavy. The draw is not subtle: tall tube slides, raft rides, a wave pool, and enough splash zones to make it useful for families with children of different ages.
Treat it as a weather-dependent outing rather than a cultural stop. Lines build on hot weekends, so arrive early, bring sun protection, and check the operating calendar before you set out; the park is seasonal and some rides close when storms roll through.