Koblenz is a 2000 year old city located where rivers Rhine and Mosel meet.
Cologne (Köln) is mainly known for: the Dom (huge cathedral), the Eau de Cologne ("parfume"), Carnival and the location near the river Rhine. Locals may also add the beer and the football club...
Heidelberg is a 800 year old university city on the Neckar river. It is a beloved touristic location thanks to its cityscape. One of the biggest tourist attractions is the Christmas market during the winter time.
München is the 3rd largest city of Germany and a highlight to any visit. It is great to have a beer here, during or outside the "Oktober fest". If you can get tickets, you may want to see Bayern Munich, one of the top clubs in Europe. The Black Forest is nearby for relaxing...
Berlin is the capital and largest city of Germany. It´s recent political history has left its marks, for example with the remainders of the Wall that separated East from West. Nowadays it is a very vibrant international city with lots of young people, startups, fashion, restaurants and art.
Frankfurt am Main is a major city and hosts the largest airport of Germany. It is also a large financial centre and home to the European Bank.
Passau is also known as the Dreiflüssestadt ("City of Three Rivers") because the Danube is joined there by the Inn from the south and the Ilz from the north. The city exists for more than 2000 years.
Aachen is a nice city, with a cosy old town, at the border with The Netherlands and Belgium. It is home to the 1200 year old Dom/Cathedral (#1 on UNESCO heritage list, since 1978).