Millions of years ago Barton Springs, the fourth largest natural springs in the state, was created as a result of a landshift that created the Balcones Fault. Found within Zilker Metropolitan Park, Barton Springs is a three acre pool powered by natural underground springs. This Austin hotspot attracts a varied crowd and is perfect for people watching, soaking up the sun and, of course, swimming. Though the temperature runs at an average of a chilling seventy degrees, the water is comfortable and refreshing. Barton Springs always has lifeguards on duty.