Chocolate museum
This nice museum is located on a small island in the river Rhine.
Taste the fresh warm chocolate from the chocolate fountain, walk through a cacao beans plantation, watch people make chocolates, watch old TV ads and enjoy the chocolate smell.
Address: Rheinauhafen 1a http://www.schokoladenmuseum.de
Boat trip on the Rhine
You can choose from a variety of trips; one hour trips, day trips and so on. I took the one hour trip on a Sunday morning and found the banks of the Rhine not that interesting but you have a nice view on the skyline of Cologne from the water.
Walk along the Rhine
The nicest part to stroll along this river is between the cathedral and the chocolate museum.
Cross bridges as Hohenzollernbrucke or the Duetzer Brucke to have a nice view of the Cologne skyline.
City gates
There are 3 preserved city gates of the medieval city fortifications: Severinsgate at the Chlodwigplatz (South), what used to be the main road to Rome runs through it; Eigelsteintor at the Ebertplatz (North), is the entrance to the Eigelstein Quarter; Hahnentorburg (see picture) at the Rudolfplatz (West), important visitors used this gate to enter the city.