The Aurès mountains breed unvanquishable guerrillas due to harsh terrain. [causal]
Searingly hot summers are succeeded almost immediately by the cutting winds of winter, and the Aurès has long suffered perhaps the most woeful poverty of all Algeria. Equally like the north-west frontier of India, which it closely resembles, it has from time immemorial been a land of unvanquishable guerrillas and banditry.
XREF: Echoes the classic pattern of insurgent sanctuaries in rugged terrain, like Afghanistan's mountains, which have long sheltered resistance movements.
Horne, Alistair, A Savage War of Peace- Alge…, loc. 146