Evans Plunge, is the world's largest indoor freshwater swimming pool heated by a thermal spring. Evans Plunge (named after its builder Fred Evans), was built in 1890 over the numerous small, sparkling springs and one mammoth spring of mineral water. Originally, Evans Plunge and the other mineral baths in Hot Springs were sought as a cure-all for a multitude of illnesses. The largest spring, at the north end of the pool in the interior of the Plunge, is known as the "Original Indian Spring." Here Native Americans drank and bathed in the spring's warm healing water. Today, numerous areas of warm sparkling springs may be felt as one moves through the crystal clear water towards the original Indian Spring.