"Cathedral of San Juan Bautista Dating to 1521, the Cathedral of San Juan Bautista isn't justone of the oldest buildings in San Juan—it’s the second-oldest cathedral in all of the Americas. Go inside to see the tomb of Spanish explorer Ponce de León, who founded the first settlement on Puerto Rico and in 1509 was named the island's first governor. The remains of St. Pio, a Roman martyr, can also be seen in the cathedral—the saint's mummy has beendisplayed here in a glass box since 1862."