Al Qadmous Castle
One of the two most famous Ismaeli castles, it was built as the first stronghold of the Ismaelis. However it was later taken by the Crusaders who called it Cademois and used it as an outpost of Al Marqab castle, not far away. It was then given to the Hospitallers in 1186, and was destroyed much later by Sultan Ibrahim Pasha of the Ottomans. The castle itself was built on a protruding rock to strengthen its immunity. 

Al Kahf Castle
Known in English as Castle of the cave, it is the second most famous Ismaeli castle. This castle was built at a junction between three narrow valleys, and was the hiding place of the Ismaeli leader Rashid al Din Sinan. The only access to it is through a tunnel like entrance, which gave it the immunity it required from attackers. At the moment not much of it remains except for the remnants of cellars, a bath and some inscriptions in which Baibars is mentioned.

Other Castles Include:
Al Arima, Yahmur, Al Khawabi, Al Aliqa, Al Quoz, and Al Sabi.