Bad- und Waschanstalt Winterthur, Historical bathhouse in Altstadt, Winterthur, Switzerland.

The Bad- und Waschanstalt Winterthur was Switzerland's first indoor swimming pool, built at the corner of Badgasse and Neustadtgasse in Winterthur's old town. The Moorish-style building, planned by city architect Karl Wilhelm Bareiss, held twelve marble bathtubs, two showers, a Turkish bath with a cooling room and a small pool of 12 by 8 metres, 80 cm to 1.8 m deep. Its horseshoe windows and minaret-shaped chimney earned it the nickname "Badewannenmoschee".

The Bad- und Waschanstalt Winterthur was built between 1862 and 1864 to plans by city architect Karl Wilhelm Bareiss, next to the former Lörlibad, and opened in 1864 as Switzerland's first indoor swimming pool. It remained the country's only indoor pool for 44 years, until the Volksbad St. Gallen opened in 1906. After the Geiselweid pool opened in 1911, the bathhouse closed in 1915. A planned demolition in 1975 was stopped by citizen protests.

The building's Moorish style earned it the nickname "Badewannenmoschee" (bathtub mosque). Its horseshoe windows and ornaments recalled the bathing culture of the Orient, and the chimney was shaped like a minaret. Bathing was strictly segregated by sex, and the baths were open only from May to October.

The building stands at the corner of Badgasse and Neustadtgasse in Winterthur's old town, under cantonal and federal heritage protection. After the bath closed in 1915 it served as an auction hall, was slated for demolition in 1975, and later housed a city police station. A wellness-bath project awarded in 2023 failed two years later over rising costs.

The building's nickname, "Badewannenmoschee" (bathtub mosque), comes from its Moorish-style facade with horseshoe windows and a chimney shaped like a minaret. The twelve bathtubs were of marble, but the sources do not specify Carrara. The pool measured only 12 by 8 metres, with a depth of 80 cm to 1.8 m.