The castle with a very dark basement
Look up. That's the Gravensteen, the Castle of the Counts, and for centuries this was the boss building of Flanders. A moat, thick walls, and one big central tower doing all the intimidating. The counts lived here, ruled here, and — this is the nosy bit — kept a torture museum in the basement long before it was a museum. These days the only thing being tortured is your calf muscles on the spiral stairs. Worth it for the view over the rooftops.