Keep Digging.

EVERY COUPLE OF YEARS, STUNNING CITIES RISE FROM FORGOTTEN EARTH. RESEARCHERS NOW believe the oldest city in the Americas--among the oldest in the world--is Caral, in the Supe Valley in central Peru, a developed town with irrigation and ceremonial mounds that flourished 4,600 years ago, before Egypt's Old Kingdom and the first pyramids there.

What's stunning is that where we think civilization began has been decided, mostly, by who has done more digging. British colonists opened trade routes to the Middle East. Wealthy Victorian hobbyist archeologists followed them and subsequently discovered ancient sites at every turn of a pickaxe in the sand. Spain's conquistadores, although they arrived in the New World centuries before England's rise, however, did almost nothing to understand the past of their conquered peoples.

Only now are U.S. and Latin American academics beginning to really dig, discovering advanced societies that practiced agriculture, built temples and made art--millenia before anyone thought was likely or possible. Before long, we may find that our deepest roots as humans run down Andean valleys to the Pacific.