The cloth hall. There is a "cat parade" in Ypres that is held every 3 years the second Sunday in May!
We went to Ypres (Ieper), Belgium to explore the battlefields in and around Ypres. Actually we've been there now several times, not just because of the history there, but also because it's one of the most beautiful towns here in Belgium.
If you are a history lover, you'll enjoy the opportunity to either take a guided tour, which is best to do if you don't have small children with you, because if they make noise and disturb the other tourists, the tour guides might ask you to leave the tour. We took a driving route ourselves with our car, which is clearly marked alongside the road by blue-white signs. Alongside the roads there are many cemeteries, monuments and bunkers. Some things, like Hill 60 and Hill 62 are a little harder to find. :)
There are also craters around, museums and remaining trenches. Definitely worth a visit.