The mineral hot springs in Tuscany's Val d'Orcia have been embraced for their healing properties since the days of the Etruscans. Adler Thermae makes use of these pools, along with thermal mud and steam, in all their treatments.
Signature Treatment: The Argillae-Rasul bath, which incorporates body smoothing with mineral-rich mud, an herbal steam, and a purifying bath (for up to 4 people; 45 minutes, $40 per person).
39/0577-889-00; www.adler-thermae.com