I think there are a few places which are more diverse and untameable than others. Places such as Madagascar, Iceland or New Zealand (all Islands) are highly unique but not as diverse as Mexico is.
Mexico has many different places within it's borders and has the rich history to go along with it. Its ancient material culture is far more present today than is the material culture of Ancient America (with exceptions such as Cahokia or Ozette Village). Toltecs, Maya, Aztecs, Zapotecs, Mixtecs and Puebloans all left impressive ruins. Also, the people of Mexico have much more Native DNA than most Americans. Maya and Aztec descendants measure in the millions, each. Deserts, tropics, coastline, highlands, mountains and canyons all lie within the border of Mexico. It is easily one of the most diverse countries geographically in the world.
Mexico is untameable, because it would take a lifetime to see half of it. There are too many cities, such as Cuernavaca or Puerto Peñasco; Archaeological sites like Teotihaucan or Casas Grandes; or geographic regions like Copper Canyone or the Yucatan. You could not see them all. And I think that is part of its draw.