Königswinter-Margarethenhöhe is a good trailhead to discover the Siebengebirge, hiking trails take you all around. There is a parking lot and a bus station of the line 521.
Mount Ölberg (468 m) is the highest mountain in the Siebengebirge. When you come by car over the A3 Autobahn (motorway, interstate) or over the Kennedy bridge in Bonn, you see it already from far.
Mount Rosenau stands in the middle of the Siebengebirge between the mountains Nonnenstromberg and Ölberg. Coming on the hiking trail that goes all around Mount Ölberg (Ölbergringweg), a path leads to the Rosenau with the ruine of a small medieval castle. You will see the signpost “Aufstieg zur Rosenau”, ascent to Rosenau.
I love Mount Lohrberg, Siebengebirge. Just walk along the loop hiking trail, sit down on a bench and enjoy the fantastic views. If you have come to rekindle with nature and enjoy great views, you will certainly love Mount Lohrberg, too.