The most iconic and impressive formation is the "White Whale" (or "Whale's Mouth"), a giant white travertine waterfall that resembles the open mouth of a whale or a glacier. The waters of Bagni San Filippo are sulphurous, sulphate-calcic-magnesium-bicarbonate-carbonic waters. They are known for their anti-inflammatory and detoxifying properties, particularly for the well-being of the skin, muscles and joints..