Mexico has such a deep and long history it is best visited by cultural era in order to better understand the country. Mexico City itself, along with much of the area occupied by the Toltecs, was swamp and as a result of building on top of building, especially in Mexico City, the whole area is sinking, even though today much of the area appears and feels dry and arid. The archaeological sites are varied but familiar to one another. As with other places, some of the brutal history of the ancient cultures is flatly denied by some local guides so it is best to have "studied up" before going and then have a trip guide who is an archaeologist of the area brings the truth of the past to the present as ours did so well and thoroughly.