We are thinking of spending a few weeks in this area next summer. I don't know much about this area of Germany and will certainly be researching on the internet. But in the meantime, does anyone have recommendations on places to go and things to do..."don't miss" ones? Thanks.
My personal experience says you can two different ways: 1) head towards Cologne/Dusseldorf area of Germany or2) head into Belgium.....especially if there is an interest in WWII. With a little research and good eyes, you'll see portions of the Seigfried Line in tact, almost as it was in 1945. Then you can venture into Belgium and head towards Liege and then on to Bastogne. If....you get a chance we found the town of Spa, Belgium interesting with a very nice Spa Resort Hotel.
There are several American WWII cemetaries in that area that would easily be day trips from Aachen. You can find them at: www.abmc.gov. If you are unfamiliar with these cemetaries you will be amazed. Travel information to them will be available at the TI office or in the Rough Guide Germany.
If you have any interest in German National Parks, the Eifel National Park sits just to the south. I've heard that the main town neighboring the park (Monschau) is worth a visit, but I haven't personally seen it. Stolberg is kind of interesting. It has a well-preserved old center with a castle and many old stone buildings, constructed in a style that is unique to the region. Maastricht in the Netherlands Limburg is also a nice city. There always seems to be some kind of party happening whenever I've visited. Liège is kind of a dump, I wouldn't waste any time there. A little further to the west, there's one of the best open air folk museum between Hasselt and Genk (Bokrijk). In the northern Ardennes, Spa could make a decent daytrip, although if you're looking for a thermal treatment, they also have plenty of that in Aachen.
I would never say what is "don't miss" because there is no one size fits all travel. One man's junk is another man's treasure, as they say. Nevertheless, my observations about my several trips to Aachen: There are lovely little shops in Aachen, some having been there quite a long time. My favourite hairbrushes are from such a one. The spa was a bit of a let down. The water was cooler than I would have liked, the facilities aimed, IMO, at more children and elderly than middle aged. Nice enough but we didn't go back because with a car the Thermae 2000 near Valkenburg in the Limburger mountains (Dutch joke) midway between Aachen and Maastricht is so much better. The cathedral in Aachen is special, not just because of its compact yet large size and shape, but because it is so old and has so many historical connections, not least Charlemagne. Just outside the cathedral is a frequent market, and the town is good for walking in. I agree that Liege did nothing for me, but Spa is interesting not least because it has one of the best Formula 1 tracks in the world and it is easy to get to. We like Maastricht - there are still several things there we haven't had a chance to see. Just into the Netherlands is one of our favourite pancake bakeries set next to ponds with walking paths nearby. The view from the patio is lovely.
Monschau is correctly reported as "touristy", but it's a much better than average half-timbered town. There's quite a lot to it, and as noted, scenic walking beside and beyond the town. It is very busy at high season. I liked walking around Monschau better than the old part of Bernkastel, Germany, which many people rave over. I've heard similar recommendations for Mönchengladbach, but I haven't been there. If your daytrip train goes through Liege, be sure to view the Calatrava train station. New York's World Trade Center transit hub was to evoke that feeling, but it's been Value Engineered into a pale shadow of it. You might be interested in the Open-Air museum (and associated amusement park) in Bokrijk, Belgium. I haven't been to Maastricht, but it often gets good reports. Coming from a post-industrial country (!), I couldn't work up enthusiasm for Zollverein Coal Mine Industrial Complex. But it is a UNESCO WHS, which is a huge recommendation. Similarly, I'd like to see the overhead subway in post-industrial Wuppertal, which figures in the movie "The Princess and the Warrior." You haven't mentioned Cologne, with the single most-visited site in Germany. Perhaps you've already been there? Even if you don't like art museums, it's worth it for the Dom and the Roman sites.
"I've heard similar recommendations for Mönchengladbach, but I haven't been there." I've been there and I would rate it as a big "Meh". It appears to be mostly a functional post-war rebuild. Probably the only reason the city gets any visitors at all is because of their famous Bundesliga team, Borussia Mönchengladbach.
Thanks everybody for these recommendations. We'll probably be there for 4 weeks so we'll have plenty of time to explore.