The Avenue of the Dead (Calzada de los Muertos) is the main axis of the city. It stretches to the north from the Citadel all the way to the Temple of the Moon. As you leave the Citadel, turn right and walk north. On the left you’ll see the "Edificios Superpuestos" (superimposed buildings) where excavations have unearthed living quarters below the present level, which were filled in with rubble in order to build the second stage.
Rather than being directed exactly north-south, the Avenue of the Dead is aligned to 16º north-west. This was apparently done purposefully to come into alignment with the setting sun on a certain date.
Next stop on your tour of Teotihuacan: the Pyramid of the Sun.