Gravensteen is one of the castles of the Count of Flanders. It's located in the middle of Gent (Ghent in English) and it's an excellent example of an early medieval castle (extensively restored).
Anyone descended from William the conqueror is also a descendant of the early counts of Flanders (Baldwin IV, V, VI, Arnulf II)1 since William married Matilda of Flanders, the daughter of Baldwin VI (1030 - 1070). These early counts built a wooden fort on the site of the present castle. The present stone structure dates from about 1180 [Gravensteen].
I especially liked the back of the castle where the kitchen was located because it hasn't been completely restored and you get an idea of what Gravensteen must have looked like for most of the last five hundred years.
Even though it was a cloudy day, the view from the ramparts was spectacular. Gent is a beautiful city.
We spent a great deal of time in the torture chamber and Ms. Sandwalk took lots of pictures of the various instruments used to "persuade" the prisoners. She also got pictures of the guillotine that was used in the late 1700's and early 1800's.
Here's one of the more pleasant images.
[Photo Credits: top [Wikipedia], all others are by Ms. Sandwalk.
1. Assuming, that is, that you are a descendant of one of his legitimate children.