The centrepiece of the Rheingauviertel, an early-twentieth-century garden suburb whose streets are named after Rhine wine villages. The square is built around a sunken garden and the Siegfried Fountain, and from late April to early October a small wine stand sets up beside it, pouring Rheingau wines by the glass to residents who bring their own folding chairs.
The result is one of the most civilised rituals in west Berlin: neighbours gathering on summer evenings to drink Riesling under the chestnut trees. It is purely local, with no tourist infrastructure to speak of — just a glass of wine, a quiet square, and the long northern dusk.