Don't feel bad if you've never heard of Bolshoi Zayatsky; it's a tiny Russian island. What makes it remarkable is that almost all of it is covered in intricately-designed stone labyrinths. The island doesn't even cover a square mile, so the mazes account for nearly everything that's on it.
Why would anyone choose to build such delicate structures on an uninhabited island? Some researchers believe that they may have had a mystical use - perhaps the island was believed to be a portal to the underworld.