Stadtbad Neukölln is a working public bath built in 1912-14 and restored with much of its Art Nouveau grandeur intact. Mosaics, domes, and richly detailed interiors make it one of Berlin's most beautiful swimming halls, even if you are visiting as much for the architecture as for the pool.
It is a useful Neukölln stop for travellers interested in everyday Berlin buildings that are still used for their original purpose.