Researchers try to find the identity of the first people of the United States of America, which leads to ancient Amazonian cave paintings, New Mexico's Chaco Canyon and ancient Mexican burial chambers.

An exploration of the rise of great American nations, from a history of monarchies to modern democracy. Plus, a potlatch ceremony in the Pacific Northwest and shell beads in upstate New York.

Exploring some of America's ancient cities, including a lost city on the Mississippi River. Plus, a group of native elders reveal ancient powers of the sky.

A look at prime examples of survival, revival and resistance that have been revealed through secret messages in an Aztec manuscripts, horse-mounted Comanche warriors and a grass bridge in the Andes.