Though it's better known as a training spot for scuba divers, Twin Lakes is the perfect place to cool off without having to fight the traffic, and the crowds, in Galveston. Just 20 minutes south of downtown off the farm roads of 288, this aquifer-fed pool is clear enough for the aforementioned training and features five sunken fishing boats, a school bus and an Airstream trailer. Above ground there are floating docks, picnic tables, overnight campsites and a snack bar. Bass, catfish, turtle and perch live in the water, and if you're not there to dive admission is only $5.