Mamula
The fortress was built by the Austro-Hungarian navy in the 1850s to guard the entrance to Boka Bay and was later used as a prison camp during the Second World War. The island has since been redeveloped as a hotel.
The submarine tunnels
Nearby, tunnels were cut into the cliff to shelter Yugoslav navy submarines. Small boats can slip inside — the abrupt shift from Adriatic glare to cold, echoing rock is the highlight of many trips.