Teotihuacan may have been the largest city in the world at one time, with a population of up to 200,000. Dating to 600 BC this well preserved compound, with two huge pyramids holds within itself a lot of mystery to this day. Very little is known about the original inhabitants of Teotihuacan, who built this remarkable city that included a well designed system of running water, or why it was finally abandoned. It is not even known what the original name of this magnificent city was. What is known is that the city's creators had an incredible gift of combining sculpture and architecture and using these gifts to build incredibly advanced structures. There is a museum and a restaurant on the grounds along with plenty of parking. Try to visit this archeological site early in the morning, if you are not on a tour, to avoid the tour busses. An early visit will also find less vendors present, who can cause distractions.