they turn the whole city into Bethlehem and townspeople all dress up, they bring in animals and trees and line all the little streets and plazas. then visitors to the town go through the stations of the Nativity, basically recreating Joseph and Mary walking through the village looking for a place to stay.

I just happened across it one time I happened to be doing Navy duty for a couple weeks in southern Spain before Christmas. One of the coolest things I've seen.