On the days of the fall and spring equinox , Teotihuacan is packed with folks who dress in white and climb to the top of the Pyramid of the Sun. They stand at the top with arms outstretched to receive the special energy of the site on that day.
If you're not afraid of a few stairs (around 250), the views from the top are excellent. Just remember the old adage "don't look down" when you're on your way back down!
Next stop on your tour of Teotihuacan: the Quetzalpapalotl Palace.