A Jugendstil swimming pool
The fishy ceramics provide a pretty broad hint as to what lies inside - this beautifully adorned Charlottenburg building houses one of Berlin's loveliest historic swimming pools.
In fact, Berlin boasts a surprisingly high number of stunning 19th and early 20th century municipal baths, which range in style from neoclassical opulence to Bauhaus glass and steel.
The problem, of course, is that in order to actually see them you'll need to go for a dip, which might not be entirely practical for visitors spending just a short time in the city.
Luckily, this particular bathhouse is as lovely from the outside as it is on the inside, allowing you to take a good look at a gorgeous Jugendstil classic without having to take a plunge.