Besancon, France

Wow, what an absolutely cool fortress complex in Besancon (population 120,000). The Doubs River encircles Besancon on three sides and a mountain rises abruptly on the fourth. Views from the citadel afford great looks at the surrounding areas. Layers of moats and walls give each part of the fortress its own area. Vauban completed the moat system in 1674. Part of the complex has been converted into a zoo.