(Photo: Day Donaldson)
The story goes that, 40 years ago, this little island in the Drina River by the town of Bajina Basta, Serbia was a popular spot for young people to swim and sunbathe. The owner and his friends decided to build a cabin there as a private getaway. It was a difficult task--all of the materials had to be rowed out through the river's swift currents.
Now it's an endearing symbol of serenity for its owners and kayakers who occasionally visit. You can see more photos at Atlas Obscura.