Termas Hippolytus, near Alcalá de Henares in the Community of Madrid, Spain, taps thermal water at 38°C, pH 7.3. Indoor and outdoor pools, a sauna, massage, and a hammam are on offer.
Insider tip — Termas Hippolytus draws on a thermal aquifer in the Madrid Basin at approximately 40.5°N, where Mesozoic limestones and gypsum-rich sediments yield mineralized water. The site is named after Saint Hippolytus, reflecting a heritage connected to Roman and early Christian use of local springs east of Madrid. The thermal waters of the Alcala corridor have been exploited since antiquity, given the area's strategic position on the Henares River route. The facility offers modern hydrotherapy in an urban-fringe setting accessible from central Madrid.