Submarine Papanikolis

The Παπανικολής is a real decommissioned Greek submarine you can actually step aboard and explore, docked right in Piraeus harbor. It's a genuinely rare experience — getting up close to a Cold War-era vessel and seeing the cramped, claustrophobic reality of life underwater. Named after a legendary WWII Greek submarine commander, it's one of the more unusual and memorable things you can do in the area.