Seven days on the beach

Vacation time is getting closer, and we've finally settled on where we want to go. Check this out. The pictures make it look great, and it's a new resort, built just last year. It's warm, exotic, lots of sand and ocean, and did I mention warm? It's on the Carribean side of the Mayan Riviera. Our departure date is still a few weeks away, but already I'm planning what to bring. The first thing I pack for any trip is appropriate clothing to wear to Mass. So that leads me to my question. Has anyone reading this been to Cancun? I would like to know where to attend Mass, and would love to tour Mexico's ancient Cathedrals as well. Anyone?