9Terme di Saturnia, Italy

Nestled in the picturesque countryside of Tuscany, the Terme di Saturnia is a natural hot spring that has been enjoyed since ancient Roman times. The thermal waters flow at a consistent temperature of around 37.5°C (99.5°F) and are rich in sulfur and other minerals, making them perfect for relaxation and healing. 

The spa features a variety of pools, including the famous Cascate del Mulino, where visitors can bathe in the free-flowing thermal waters in a stunning natural setting. The area also offers wellness treatments and fine dining options, allowing guests to enjoy a complete sensory experience while surrounded by the breathtaking Italian landscape.