Der Kölner Dom (The Cologne Cathedral)
This huge cathedral is a fine example of Gothic architecture. It took over 600 years to build it. It's the biggest and most famous building of the city. You can climb (about 500 steps) the south tower to have a fantastic view over the city.
Address: Domkloster 4 http://www.koelnerdom.de/
Domplatte
This is the square in front of the Cathedral. It's a place where many chalk painters, skaters and other artists hang around.
Address: In front of the cathedral
The Roman-Germanic museum
Did you know that Cologne is Germany's oldest major city and the layout of the main city streets (The Hohe Strasse) still is the same as in Roman times? This museum is dedicated to this Roman past of Cologne.
Römische Hafenstrasse (Roman street)
Between the Roman-Germanic Museum and the Cathedral there's a small old Roman street. This street goes all the way back to the 3th or 4th century BC and was discovered in 1969.