The two obvious excursions from Akhalkalaki both lie to the northwest, along the Mtkvari river valley. Vardzia is the cave city carved into a cliff in the 12th century — the high point of any visit to this corner of Georgia. Akhaltsikhe is the regional capital, with a heavily restored Ottoman fortress and the only halfway decent restaurants for a hundred kilometres around. Both can be done by marshrutka in a single day if you start early.
