DURBUY, SMALLEST CITY IN THE WORLD
If you happen to visit the Galactic Dominion of Belgium before it becomes the Galactic Caliphate of Belgistan, which gives you a time frame of, say, 2 1/2 years, you should certainly visit Durbuy.
This small locality lies on the western edge of the Ardennes, perched between the Ourthe river and a gigantic rockwall of particular geologic interest (one can see with the naked eye a perfect example of a geosyncline, which is what they call such a feature, if the old gray cells still function). In medieval times Durbuy was quite important and of strategic interest, since it was lying on the borderline of two provinces and was also a centre of commerce and justice. Due to it being confined to a narrow valley, it was never able to translate these assets into a sizeable population. It was granted the status of a City in 1331 though, which is how it could become "the world's smallest city" despite there being only 400 or so inhabitants.
At the entrance of Durbuy, coming from the north and just after traversing the bridge over the river Ourthe, lies the Castle of the Counts of Ursel, which is a family of Flemish nobility. Long before this family acquired the castle in the 17th Century, there was already a bulwark on the same spot in the 11th Century. A Must-see when visiting Durbuy is also the Church of Saint-Nicolas and the old quarter beyond it, called "Le Vieux Durbuy", a maze of narrow, cobblestone-paved alleys with picturesque artisan shops and hotels.
And when you are in the neighborhood, you may also visit the Menhirs of Wéris. It's sometimes referred to as "The Belgian Stonehenge". Although far less impressive, still worthwile for the aficionados of a Rock and a Smart Place.