Men and women wear ornate dresses and masks with bushy fake facial hairs to mimic the Spanish occupiers.

Participants jump up and down and spin around in a parade that goes on for hours.

Expressions of faith as much as irony, revenge and humor have long provided themes for the dances and festivals of Mexico and the masks that belong to them.

Hugo Lopez is an ethnology professor at the National Institute of Anthropology in Mexico City. He studies the way the Mayan culture used masks.

Lopez says the complexity of the meaning of the masks isn't down to appearance alone.

And mask collector Isak Kamarek says Mexican masks appeal to human emotions rather than the intellect.

He says that when artists work on pieces of Christian art, their work is bound by strict rules of form. But when they return to creating pagan masks they are much more free to express themselves.