This impressive San Antonio resort is one of Marriott's largest properties. It's also home to the River Bluff Water Experience, six acres of heated pools, waterfalls and water slides. Daredevils should head straight for the 275-foot Acequia Tube Slides. Choose from two exhilarating options — one open-air slide and another that is mostly enclosed — before torpedoing down into the pool. Lined with cypress trees, the 1,100-foot-long lazy river is the ideal place to recuperate.