A natural fortress

Authion is a natural fortress which is virtually unconquerable, protected by its immense and steep slopes which "tower 1500m above the valleys of Caïros, Roya and Bévéra".
The relief provides no refuge, no hiding place for attackers who are extremely vulnerable.  “You only need a very few men in a dominant position to completely close off access”. (Général Y. Gras).
At the very top, the summits which tower over the 2000m mark are equipped with fortifications which the “the gigantic field work and network of mines” make impregnable.
Just one weak spot: the south!