Zerostrasse is Pula's underground counterpoint to the Roman arena and sunlit forum. The tunnel system was built during the Austro-Hungarian period as shelter and military infrastructure, cutting beneath the hill in a cool, echoing network that shows another side of the city's strategic past.
Today the tunnels are used for exhibitions, including material on military history and the city tramway. It is not a long visit, but it is memorable because the setting does so much of the work: stone, damp air, and wartime engineering under a city better known for antiquity and the Adriatic.