That's not just any temple. When the Aztecs discovered that city, they gave it a name in their Nahuatl language: Teotihuacan means "place of the gods" because

That's not just any temple. When the Aztecs discovered that city, they gave it a name in their Nahuatl language: Teotihuacan means "place of the gods" because they had no idea who built that city, and to this day no one has figured out the origin. 2 millennia ago, it was the largest city in the Americas, covering 30 sq km. The mystery can take your imagination on a wild ride, and I half-expected to see the Predator dropping down out of the sky as he made his rounds on the world's pyramids. ;) I recommend you visit, because it's quite accessible via a half-hour bus ride from the north station in Mexico City.