Callejón de los Sapos
This narrow and charming pedestrian lane, whose name means "Alley of the Toads," cuts diagonally behind the cathedral. The adjacent square has a bustling weekend antiques market with all sorts of Mexican art and crafts, from elaborately carved doors to small paintings on pieces of tin offering thanks to a saint for favors. There are also hip cafés filled with people listening to live music on weekends.