Freiburg im Breisgau is an old musical university town in the south of Germany. It can be roughly considered as the entry point to the Black Forest from west. Whereas it has all the charm to host you for an overnight stay (or multiple night stays, if you are interested in black forest locations near to it), you can cover most of it in few hours. Regular train connections on Deutsche Bahn can take you to the city main station (hbf), and it is well connected through bus routes also. For a day trip, Baden Wurttemberg Ticket is great, you can take regional bahns and public transport for a very reasonable price, and it also allows you to take a bus to nearby locations in the forest region.
The city has a rich history, from the era of Holy Roman Empire (when the region used to be part of Margrave of Baden) and as far as I know, it used to be a part of the Schwabia region of old Germany. History is just one part, the current conditioning of the city is an experience worth having. I always find it amazing how a tiny place with just simple buildings and some warm hospitality can leave an everlasting imprint on your soul. The city boasts of its university and the Cathedral.
You can walk or take a tram to the Muensterplatz, the historical heart of the city. This old cathedral will easily consume an hour or two of your visit's overall duration. The entry is free and there is a lot to see inside. The platz is most of the time active with festivities and if you happen to be there is summer then be ready to enjoy some local stuff from nearby regions (including France and Switzerland). We had some superb cider and bratwurst. Around the muenster is also the historical Kaufhaus and some other old buildings, and the way tiny streets end into this square is nice (well, not a new thing in Europe, but still!). Little far in different directions you can reach other historical locations of the town, i.e. Schwabentor & Martinstor (two oldest gates), Rathausplatz (the old townhall) etc.
The main attraction, literally at the top of the city, is the Schlossberg. An old fortified castle stood at around 450m on top of a hill since few centuries. Although the ruins are not available for the public view at present, there is a tower in place of it. The berg can be reached on foot, and you will cover some nice viewpoints. The view over the city from 100m and above is scenic! On a sunny day, you can spend hours sitting on the top or at an intermediate halt with a flagpost and compass. The top is windy and even though it is one of the warmest places in the country, you will love it. The panorama of Freiburg from this position is totally worth the effort of climbing. Well, to a certain height you can also take the lift placed there by a Biergarten (which again, is not bad if you are thirsty or hungry).
The town has Dreisam river passing through it. Old sewer canal (Bachle) runs through the whole city, and it is still well-preserved by the citizens. I was told that it keeps the surrounding cooler during summer but initially I did not believe it, given the size and amount of water. But, once you go through the colorful and musical streets, you will feel the coldness of water accompanying you on hot summer days. Children playing, and people sitting with their feet dipped in canal's water and huge mugs with some frothing coffee in hands. They call, it in America- FEEL!
Few of the famous and most scenic sections of Balck Forest can be reached by bus/train/car from this place in very short duration. We continued our trip from here to Titisee and then to Feldberg.
Freiburg is a place where I would always be ready to return, if for nothing then to just sit in shade, sip some good local wine and read a dreamy novel. Feel!