The castle of Besançon is located in the south of the city of Besançon. This castle occupies a dangerous terrain and is mainly composed of two fortresses. They are located at the diversion of the Du River, and they are watching this strategic place all year round. Besançon Castle was built in 1668, and was renovated and completed by Vauban, a famous French military engineer from 1688 to 1711. After that, it was once decorated with splendor and became the barracks and military academy of Louis XIV. Although the Besançon castle has been converted into a zoo and aquarium today, the historical relics are still everywhere.