re: What is your favorite civilization in history?

The Mayans. Lived for thousands of years in South America, built thousands of precisely engineered cities, temples, and observatories, conquered massive amounts of territory, traded all the way up to North America, had an elaborate government consisting of city-states, developed reading/writing, astronomy, mathematics, etc.

And then, one day- they up and left every bit of it behind, moved to the Yucatan peninsula in southern Mexico, and started rebuilding from scratch. Why? No one knows.

The only way we would know is from their manuscripts, which were almost entirely destroyed by the Spanish priests (heathen teachings). Because of the Spanish we lost history that dates back for many millenia.