The Vieques Conservation & Historical Trust was established to help save Puerto Mosquito, one of the last remaining bioluminescent bays in the world. The small museum, located on the main drag in Esperanza, has interesting information about the bay, as well as the island's flora and fauna and history. A little pool lets kids get acquainted with starfish, sea urchins, and other denizens of the not-so-deep. There's also a tiny gift shop whose profits are funneled back into the foundation. Call ahead if you're coming at lunchtime, as the place is sometimes closed for an hour or more.