One more borderline case. Until 1963 it was Flemish, then, by a typical belgian thingy, it became Walloon. I will not dive in that history here, especially since an other part of its history is more interesting (and funny).
Fort Eben-Emael (on the first three pictures) was built between 1932 and 1935 to stop a potential German attack in the region Luik. Military experts in several European countries judged the fortress impregnable. Military experts in Germany judged otherwise. The latter proved to be correct: in the German operation Granit, which was the start of Fall Gelb (the invasion of belgium and The Netherlands), the fortress was attacked on May 10 1940 at 4:25 in the morning. 15 minutes later the firing power of the fortress had been reduced to nearly zero. During the night the fortress got entirely surrounded by German troops (who were of course attacked from other sides), in the early morning of May 11 German troops entered the gigantic fortress, at 12:15 the same day the fortress was surrendered. From impregnable to surrendered in not even 32 hours ...
A more romantic story is the one of the tower of Eben-Ezer (on the last three pictures). It was designed and entirely built by the self educated artist Robert Garcet. On top of it are the four cherubim of the Apocalypse: a bull, a sphinx, a lion, and an eagle.
You'll find all of my Eben-Emael photos here on Pinterest.