In central Tübingen, the Neckar divides briefly into two streams, forming the elongated "Neckarinsel" (Neckar Island), famous for its "Platanenallee" with high plane trees, some of which are more than 200 years old. Pedestrians can reach the island via stairs on the narrow ends leading down from a bridge spanning the Neckar. During the summer, the "Neckarinsel" is occasionally the venue for concerts, plays, and literary readings. The row of historical houses across one side of the elongated "Neckarinsel" is called the "Neckarfront" and includes the house with adjoining tower where poet Friedrich Hölderlin stayed for the last 36 years of his life, as he struggled with mental instability.