As you can see, it's layer after layer of several temples built one on top of the other. The site was truly excavated the year I was born, when they discovered a huge stone with the image of the goddess of the moon.
The temple has also an amazing museum, which was completed not too long ago. There are beautiful artifacts, some reconstructions, mosaics, statues, and much much more.
Another place my boss and I went to was the Palacio Nacional, the seat of the Mexican government, which is covered by beautiful murales done by Diego Rivera (which, amazingly, not many people in the U.S. know about, and if they do, it's because they watched the movie "Frida", he he. He is definitely the most famous painter in Mexico's history).