The submarine pens near Herceg Novi are concrete-and-rock military tunnels from the Yugoslav naval period, cut into the coast where the Bay of Kotor narrows toward the Adriatic. They are stark, strange reminders that this beautiful bay was also a strategic naval landscape.
They are usually seen from the water on boat trips rather than as a polished museum attraction. The appeal is the contrast: Cold War infrastructure, clear water, and steep Montenegrin mountains all in the same frame.