1. Waco Surf | Waco, TX
The Waco Surf is billed as being the world’s longest (the website says ‘allegedly’) lazy river, which is nearly a mile long. You must purchase a Wedge waterslide pass to ride the lazy river, but that just increases the fun. You can also separately surf on a two-acre lake or try the wakeboarding cable park where overhead cables pull you around the water with no boat involved.