This building sits about 1000-2000 ft north of the famous Tulum Ruins. It's on its own, outside the Tulum wall, seemingly cutoff by jungle and beach. It's not part of the active tourist site as there was no one in sight. Even though outside of the ancient wall, I'm guessing it's part of Tuum in some way perhaps as a lookout or lighthouse, but I can't find anything on the internet as to what it might be. If anyone knows anything about it - please comment.