For a day by the water with a difference, plan an excursion to the steaming pools of Mortons Warm Springs. This spot is known for its mineral-rich waters.
You'll soon see why this Glen Ellen naturally heated water source is visited by many travelers. If you're looking for more to explore, Jack London State Historic Park, Quarryhill Botanical Garden, and Oakmont Golf Club are in the area too. They won't take long to reach from Morton's Warm Springs.