Armenia has numerous caves all over the country. The most important karst area is the Vayots Dzor Region at Yeghegnadzor, which is the only north-south connection of the country. Arjeri cave (Archer cave - Bear Cave), which is located here, is the longest and deepest cave of Armenia (L=3,000 m, VR=145m).
Armenia also has volcanism and some lava tubes. The longest one is Sanahin Cave, which is 100 m long.