Cologne was a great medieval city and the Ulrepforte and city walls that can still be seen really give you a sense of what the city would have been like in the days of the Holy Roman Empire. Cologne Cathedral is a must see for any visitor to the city. The Hohenzollern Bridge is also quite an extravagant example of industrial architecture and know how. If you are on a tight budget,
Ibis Koeln Airport hotel is not bad and you can even find a discount hotels. Cologne is easy to navigate and you can find out all you need to know in numerous travel guides.