Like many cities, Munich started out as a small town enclosed by a wall and then expanded beyond it. The 'inner city' occupies such a small area that everything is close and easy to visit, and you'll get a sense of the original wall, indeed, the gates still remain.
The river Isar flows through the city and it is generally a very green place. The enormous Englischer Garten, is a park with a boating lake and is well worth a visit.
You could lose yourself for days in the Deutsches Museum or in any of a number of the other museums and galleries and there are countless beautiful churches and other buildings to explore.
Besides all this, Munich is a soccer capital with no less than three clubs playing in the Bundesliga, the German equivalent of the English Premier League. The incredible Olympic Stadium complex, Olympic tower and park built for 1973 Olympic games are necessary on the visit list.