Freising is a small Bavarian city about 35 kilometres north of Munich and just a few kilometres from Munich Airport — which makes it both easy to reach and surprisingly overlooked. It's one of the oldest cities in Bavaria, with a history stretching back to the early medieval period. The bishop's seat here predates Munich itself, and for centuries Freising mattered more than its famous southern neighbour.
The Domberg hill above town is the main reason to visit: a cathedral complex of real beauty, anchored by the Cathedral of St Mary and St Corbinian, whose Romanesque crypt dates from the 11th century. The attached Diocesan Museum holds an excellent collection of Bavarian religious art. The old streets around the Marktplatz below are pleasant without being showy.
Freising's other claim is Weihenstephan, a Benedictine monastery on a hill at the edge of town that has been brewing beer continuously since at least 1040 — making it the oldest operating brewery in the world. The Bräustüberl on-site is the obvious place to sample the results. Weihenstephan is now also home to the Technical University of Munich's brewing faculty, which gives the whole operation a suitably rigorous academic weight. The Sichtungsgarten — a remarkable botanical trial garden on the same hill — is worth an hour of anyone's time.