Atskuri Fortress, Medieval fortress in Samtskhe-Javakheti, Georgia

Atskuri Fortress stands on a high cliff on the right bank of the Mtkvari River, about 30 km from Borjomi. It covers a vast area made up of several parts, with the citadel at the highest point. Its territory includes the ruins of a church with remnants of frescoes, and a water-supply tunnel connects the fortress to the river.

First mentioned in the 9th century, Atskuri Fortress guarded the Borjomi Valley from the south. The Ottomans occupied it in the second half of the 16th century and rebuilt it in the 17th–18th centuries. A joint Russo-Georgian army besieged it in 1770 without success. The Treaty of Adrianople freed it from Ottoman rule in 1829, and it was abandoned soon after.

The fortress walls display building techniques from different periods, showing how Georgian military construction evolved over time. Visitors can see these changes directly in the stonework as they walk through the structure.

Access is via a narrow tunnel cut into the rock, the same passage defenders once used; the interior was hard to storm even after an enemy entered the tunnel. The fortress is no longer a whole structure, and after its collapse on 19 August 2009 consolidation work was carried out in 2013; it remains close to ruin, so keep to stable ground.

A hidden tunnel was carved into the rock to provide defenders with water access during long sieges. This underground passage shows the military engineering skill that went into protecting the fortress.