Kaunas IX Fort Tunnel System

The Kaunas Fortress — a vast ring of defensive forts built by the Russian Empire around the city in the late 19th and early 20th centuries — contains an extensive underground tunnel system connecting the individual forts. These brick-lined passages, designed for troop movement and ammunition transport, represent one of the largest underground military networks in the Baltic region. While the most famous fort is the Ninth (now a Holocaust memorial and museum), the tunnel systems of the other forts — some accessible, some sealed — reveal the engineering ambition of the fortress project. The tunnels feature vaulted ceilings, ammunition niches, ventilation shafts, and connecting galleries. Exploring the accessible sections provides a visceral sense of the fortress's scale and the conditions soldiers endured within.