Day trips from Brussels

Cologne is 2 hrs each way as is Haarlem, Delft, The Hague, Gouda, etc.
Might consider Antwerp or revisiting Bruges and Ghent - shorter commutes and more time spent in the city. Of course, depending on your schedule, you could take more than one day trip...
Find what interests you and suits your needs and go with it!

I liked Dinant.

With four nights in Brussels, you might want two day trips. For one, I'd suggest Ieper. It probably means a train change in Gent, but is definitely still worthwhile for the Great War museum, sights and surrounding history tours. An easy choice would be to go Waterloo, and visit the sights where Wellington and allies defeated Napoleon.

The Waterloo battlefield is only a bus ride away.

Many thanks, for the suggestions!

We had an easy and lovely daytrip via train from Brussels to Dinant.

I posted a similar question on day trips from Ghent (https://community.ricksteves.com/travel-forum/belgium/less-obvious-ghent-day-trips), which may address your question. Mechelen Was a good day trip and Antwerpen always seems to pull us for a day trip when we base ourselves in Ghent every year.

If you can get cheap advance purchase rail tix, Cologne is a walkable city very suitable for a long day trip. I’d spend the night.

I’m surprised you haven’t been to Antwerp yet. It’s a much nicer place to stay than Brussels, if farther from the airport. Lier and Turnhout pair well for two rushed half-day visits. Mechelen is very nice, with a Saturday market. Leuven is nice, and close to BRU.

I don’t know why others assume you’re interested in WW2, but you could consider the frightening Breendonk fort/Nazi prison. Free audio guide includes English. Hard to do by public transportation. See Wikipedia about “the Mechelen Trials.”

so the consensus here is to skip Brussels in favor of Antwerp then?

I vote for Waterloo only if you are deeply interested in the history. The museums there were expanded for the 200th anniversary of Waterloo. If not, then I suggest Mons.

I disagree with the idea that Antwerp is clearly preferred to Brussels. I enjoyed visiting both. There was plenty to do in both. I don't understand why some people are so down on Brussels.

Actually Eugene, I don't think anyone said to SKIP Brussels. A few people said that they had enjoyed Antwerp more than Brussels, so they suggested that the OP consider sleeping there instead of Brussels. I'm one of those with that opinion. It's also frustrating to see artificial attractions like the European Parliament building and the Atomium given such "must-do" importance. I've never been to either, and I've spent at least 6 weeks in Antwerp. Brussels has lots of architecture and history, but it's much less charming than Antwerp's. Internet newsboards work on "Opinion". The "best" city is not a "fact", it's an "Opinion"!

There are a few reasons for sleeping in Brussels, mainly transportation. It's easier to get to the airport, and it's easier to get to other major cities and other countries from Brussels. The Eurostar train from London stops in Brussels, at a secondary downtown station, not Centraal. (Free change to Centraal or Nord station.) But the trains from Brugge-Gent-Antwerp-Mechelen to Brussels are very frequent, several an hour, and relatively cheap. It's also a question of whether you want to stay in a place where you might enjoy spending the most days. OTHO, it's easier to get to Lier and Turnhout from Antwerp. And a few high-speed trains to other countries do stop in Antwerp.

Now, with the best art museum in Antwerp closed for renovation, there's an argument for art fiends to stay in Brussels. But there are many other museums in Antwerp, and some of the KMSKA works are on exhibit anyway.

Brussels has a fine art museum. It also has the Musical Instruments Museum which has a wonderful system of audio guides that lets you listen to how each instrument sounds--and it is in an Art Nouveau building as a bonus. It has a great military history museum and the Horta Museum. These aren't made-up attractions. The Grand Place and the shopping arcades are good places to linger. The puppet theater is worth a performance. We saw "Romeo and Juliet" there. It was in French, but we knew the plot well enough that we didn't need translation.