What is the importance of Oaxaca in the novel, The Eagle’s Gift?

Oaxaca is a town in southern Mexico, site of archaeological ruins at Monte Alban. La Gorda roams the ruins long ago, despite Don Juan Matus' warning to avoid them. She usually goes with Pablito, but it is during a visit with Nestor that she sees a glitter on the ground, digs out a strange rock, and is overtaken by its power. In Oaxaca, narrator Carlos Castaneda and la Gorda sit on Don Juan's favorite bench, fall asleep but conscious, leaning their heads together, and each sees the crowd that gathers around them as luminous blobs that coalesce into large, oblong eggs. La Gorda is certain that she sees Don Juan and Don Genaro a block away, but chasing them achieves nothing. They vanish.

Carlos returns alone to visit a house that stir feelings but reveal no concrete memories. He drives the apprentices to Oaxaca when they agree that they must leave their mountain valley homes. Discussions of the two strangers who vanish convince them that they must go north. They find places in a local boardinghouse. The men finish up business they have in town while the women shop for Western-style clothes.