Río Piedras is the Puerto Rican answer to a college town. The University of Puerto Rico is the engine that drives the neighborhood. Thankfully, it has given rise to Río Piedras' most interesting sights. From a fantastic museum with priceless local works and artifacts to a botanical garden that is easily one of the best you'll find in the Caribbean, this rather nondescript part of San Juan merits a day of your time.

But don't plan on an extended stay here, and don't look for a hotel reservation. The rest of San Juan beckons.