Have your ever thought about swimming through the submarine tunnel? Well, there are places you can do that. Former Yugoslavia includes countries of Slovenia, Croatia, Bosnia and Hercegovina, Serbia, Montenegro and there are several tunnels in Croatia and Montenegro. Please have a closer look at this amazing article of how and where you can do that.
More details about swimming in the submarine tunnels.
Here is the video of swimming the Hitler’s Eye Submarine Tunnel in Sibenik, Croatia: