A mock medieval castle on an island in the Spree houses this former Cold War–era youth club turned cultural centre. It's especially popular in summer when you can ride your bike down the river to chill in the beer garden or rent a boat. Organisers also run an eclectic spectrum of events ranging from open-air cinema and concerts to parties and poetry slams.
In winter, the cafe serves Sunday brunch from noon to 6pm. It’s just off Treptower Park in the southern district of Treptow, about 1km northeast of S-Bahn station Plänterwald.