Known simply as ‘La Catedral,’ this bright, canary-yellow church fronting the plaza was begun in 1647, destroyed in 1759, and rebuilt soon afterward. The cathedral has a famous basilica (but unless you are attending mass, you have a one-hour window each day to pop in) and a museum of religious and colonial art that is pricier than it is worth, though there are intriguing frescos in the downstairs basement (along with a few bats).
