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...
Koblenz is a 2000 year old city located where rivers Rhine and Mosel meet.
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.
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).
The Chiemsee (aka. the Bavarian Sea because of its size) is a lake in the province of Bayern.
Garmisch-Partenkirchen is an Alpine city on the border with Austria. The Zugspitze (highest mountain in Germany) is nearby. The city is known for great skiing including famous ski-jumping tournaments.
Hamburg is a major harbor and has nice sites and cafes. The old Speicherstadt and new Opera Building feature great architecture. Also worth visiting is the Miniature Wunderland, a very large, running model train that features many world sites. And yes, it's most famous, world-renowned citizen is the edible Hamburger!
Loreley is a small city in a very scenic environment. Most visitors see the place either from a river Rhine/Mosel cruise or on a bicycle tour. Loreley is also in a great area for excellent German white whine...