Horseshoe Bay Resort, a golf and lakeside resort less than an hour outside of Austin and set in Texas Hill Country, opened the new pool on the edge of constant-level Lake Lyndon B. Johnson.

Not many natural pools can boast their own waterfalls ... the Barton Springs Pool in Austin, Texas, covers three acres and maintains a temperature of about 68 degrees year-round.

The 232-acre Hamilton Pool Preserve includes trails, picnic areas and a swimming area, according to the county.