We spent a good 5 hours exploring this vast WHS. Teotihuacan is a place that you should consider careful planning. Firstly, besides what you may find online, its open on Monday. Secondly, prepare for the sun and purchase water. Thirdly, don't think the Pyramid of the Sun is the only highlight of this huge site. Lastly, arrive early before the buses of tourists and vendors. Despite these realities, the site is so vast the numbers make no difference unless you are hiking up the Pyramid of the Sun after 11am.

The best view of the site, is without a doubt from the Temple of the Moon looking out over the Avenue of the Dead and the Pyramid of the Sun. Nearby, is a ruined palace site that includes original (& recreated) paintings of this ancient Mesoamerican culture.

I very much enjoyed my time visiting this site, and it should not be missed by anyone who visits Mexico City. On a side note, the Aqueduct of Padre Tembleque is located somewhat near Teotihuacan. At this point I know of no easy way to visit both WHS using public transit in one day. Yet, I am sure this will eventually become a reality.

Seemingly, an inevitable tourist activity when visiting Teotihuacan is hiking the Pyramid of the Sun. The view is certainly special and the climb makes you appreciate the size and labor involved in its construction. If its very busy, consider other views and places to explore, but if you have the time, inclination, and water you might want to make the attempt.