Belgium is a compact country packed with amazing architecture and medieval castles. There are around 3000 castles in the country which has one of the highest density of castles per square km in the world. Some regions have an average two castles per village. There are approximately 400 of them open to public.
The most significant and stunning however are:
Beersel (near Brussels)
The castle is one of the few well-kept examples of a Middle Age fortified castle. Even now it still looks the same as at the end of the 15th century. The castle was built between 1300 and 1310 to protect Brussels. It was under siege and plundered by the Brusselaars and was partly rebuilt in 1489. The peaked roofs you may observe are from restoration. The date 1617 which you can see on one of the towers is there from another restoration. The castle with its moats, high and thick walls and towers was almost impossible to conquer.
This 13th-century castle somehow resembles Disney castles with turrets, towers, a drawbridge, a moat, and the spirits of all those who have, willingly or unwillingly, resided within its walls. It looks like the ideal place for pulling up the drawbridge and settling in for a siege
Gravensteen (Ghent)
Even 900 years after it was constructed, the castle of the Counts of Flanders in Ghent can still summon up a feeling of dread as you peruse its gray stone walls. It's a grim reminder that castles were not all for chivalrous knights and beautiful princesses. This one was intended as much to subdue the independent-minded citizens of Ghent as to protect the city from foreign marauders. Inside are the tools of the autocrat's profession: torture instruments that show that what the Middle Ages lacked in humanity they made up for in invention.
Today, the Gravensteen has been beautifully restored. It is still partially surrounded by the medieval moat. It can be visited all through the year. Inside of the rooms is a museum about the history of prison life and organization, with a collection of medieval torture instruments of course.
Bouillon (near Dinant in the Ardennes)
Bouillon is a small town at the Belgo-French border famous for its medieval castle. Duke Godfrey of Bouillon once used to own it. Nobody knows precisely when the castle was built but the present fortifications were constructed between 1050 and 1067. This castle-fortress is one of the most ancient and interesting remains of feudalism in Belgium with the first fortifications. It was built on three rocky outcrops overhanging the Semois river and is characterized by a labyrinth of corridors and huge vaulted halls. The castle became first famous due to Godefroid, an acknowledged defender of Saint Spulcre and the leader of the first Crusade (1096). In order to finance his expedition to the Holy Land, he mortgaged the castle with the Archbishop of Lige. During the wars of Louis XIV it underwent large-scale refurbishments by Vauban.
The castle still stands today, atop a steep bluff overlooking the town, the bridge over the Semois River, and the road to Paris. Modern town Bouillon,
Belgium now has a few schools, a gymnasium and banks. It is still a small and magnificent town attracting lots of tourist
