Sole Uno is the wellness world of the Parkresort Rheinfelden, 16 km east of Basel, with an intensive brine pool for floating and a textile-free sauna garden running down to the Rhine. Indoors there is a 90°C Finnish sauna with hourly Aufguss, a bio sauna and a steam bath; outdoors a half-buried earth sauna at 110°C, a fire sauna with a central fireplace and a Siberian log banya hosting Wenik rituals, plus a cold plunge pool. Entry from CHF 33 for 2 hours; open daily 8 am to 10:30 pm, age 14+.