Proteus II S-113

This is where you can step inside a real Hellenic Navy submarine, the Proteus S-113, converted into a walk-through open museum right on the Faliro waterfront. It sits within the Naval Tradition Park alongside the famous battleship Averof and the trireme Olympias, making this one of the most unique open-air maritime heritage sites in Greece. It's genuinely rare to get this close to Cold War-era naval hardware — and the whole park covers 26 acres of seafront history you can actually explore.