The place where the three rivers merge is called “Three Rivers Corner” (Dreiflüsse-Eck). The corner itself is located on a peninsula between the Danube and Inn, where the Old Town of Passau is also situated. In fact, the "Three Rivers Corner" is a small park. The area adjacent to it is called Ortspitze - from the words “place” (Ort) and “edge” (Spitze). There is a track in the park along the water edge and a few benches, sitting on which you can meditate, looking at the water.
By the way, it is here that you can (and should) see the differences in color of the three rivers. If you see and agree that the Danube is blue, the Inn is green and the Ilz is black, then you are a true resident of Passau. The task is difficult as the rapid flow of the Danube and green water of the Inn impede the task performance. But it is worth trying!