Of Munich’s original five gates, only three remain: the Karlstor, Isartor and Sendlinger Tor.
Karlstor
A good way to visit Munich’s inner city is by starting at the Karlstor (Karl’s gate). This gate was part of a large 14th century city wall which replaced the smaller city wall from the 12th century.
The city wall was destroyed at around 1800, and the Karlstor became the center of a new square, Karlsplatz (a.k.a. Stachus). Two buildings were built next to the Karlstor, forming a symmetrical half circle, symbolizing the opening of the city towards the outside.
Neuhauserstrasse
The Karlstor is now the gate to the main pedestrian zone in Munich. The street connecting the Karlstor with Marienplatz (the main square in Munich), the Neuhauserstraße, is the most important shopping street in Munich. Is overly crowded on saturdays, 
but on other days, it takes about 10 minutes to go from the Karlstor to the MarienPlatz.
Isartor
Another one of the three remainders of the city fortifications, the Isartor (Isar Gate) can be found west of the Marienplatz, at the end of what is called the ‘Tal’ (valley). The street, Im Tal, is called as such because in the past the road from the Old Town Hall towards the Isartor went downhill. The tower was built in 1337 and was the main thoroughfare towards the Isar, the main river flowing through Munich. The facade of the Isartor is ornamented with a painting depicting the Battle fought by Ludwig der Bayer in 1322 at Ampfing.
Sendlinger Tor
The oldest of the three gates in Munich is the Sendlinger Toror Sendlinger Gate. The gate, first mentioned in 1318, once led to the trade route to Italy. It was a part of the outer city wall. The main tower in the middle was destroyed at the beginning of the 19th century; two hexagonal side towers and the walls were restored in 1860 by Zenetti. In 1906 the three original arches were replaced by one large arch.