The historical city of Ghent and the areas around it are host to several historic castles. In the city of Ghent itself, the “Gravensteen” and “Geeraard the Devil Castle” are worth a visit, and within walking distance.
Het Gravensteen
The Gravensteen (in Dutch “Castle of the Counts”) is a medieval castle in Ghent, Belgium that dates all the way back to the reign of Arnulf I, the first Count of Flanders (890–965). The site, first fortified around the year 1000, burnt down in around 1176.

The current castle dates from 1180 and was the residence of the Counts of Flanders until 1353. The Gravensteen was intended to intimidate the inhabitants of Ghent who often challenged the counts’ authority. It incorporates a large central donjon, a residence, torture chamber and various smaller buildings. The castle also has a sizeable moat, fed with water from the Lys.

Throughout its existence, the castle has been re-purposed as a court, a prison and a mint. During the Industrial Revolution, the Gravensteen was converted into a cotton mill by an industrialist who purchased the site. During this period, the castle served as a production facility with dwellings for about fifty families of workers.
When the mill and its workers left, the Castle of the Counts was in a state of complete disrepair, ready for demolition. It was restored over 1893–1903 and is now a museum and a major landmark in the city. The Gravensteen was the centrepiece of the Ghent World Fair of 1913 and is accessible to members of the public. Tickets can be purchased online via the city of Ghent website.
The Geeraard de Duivelsteen
The Geeraard de Duivelsteen (“Geeraard the Devil Castle”) is a lesser known castle within walking distance from het Gravensteen. The historic building was named after the knight Geeraard Vilain, who lived from 1210 until 1270. Vilain’s nickname, “Geeraard de Duivel” (“Geerard the Devil”), referenced his dark complexion and hair color.

In the 14th century, the building became property of the city of Ghent. It went on to serve various functions: gatherings of knights during medieval times, as an armory, a monastery, a school, the seminary for the diocese of Ghent, a prison and even an asylum for the insane.

Unlike het Gravensteen, the Geeraard de Duivelsteen is currently not accessible to visitors. However, this might change in the future: the castle was sold for 2.2M EUR in 2016 (a reasonable rate for a castle) and will likely be open to the public in some form in the future.
In any event, the Gravensteen and Geeraard de Duivelsteen are within walking distance, and definitely worth checking out. This walking route is about 15 minutes and takes you through some of the historic highlights of Ghent (Google Maps):
