Château de Vincennes
At various times in its history, the Château de Vincennes has been a royal residence, a porcelain factory, a prison and a burial site. Its location was designed to allow the monarchy to keep a watchful eye over Paris.
Now, with a metro stop named after it, it's a part of the French capital. Highlights include the highest fortified tower in Europe and the beautiful Gothic Sainte-Chapelle de Vincennes.