Vieques National Wildlife Refuge

A sliver of land between Puerto Rico and the U.S. Virgin Islands, Vieques Island is capped on the east and the west by nearly 18,000 acres of the most ecologically diverse land in the Caribbean. The Vieques National Wildlife Refuge protects more than 15 endangered animals and plants that inhabit its mangrove wetlands, coastal lagoons, and subtropical forests. The refuge once shook with WWII-level explosions when it served as a U.S. Navy practice range. But the faux war stopped in 2003, and today the island houses one of the largest refuges in the Caribbean. White coral sand beaches line the sea, looking out on a field of sea-grass beds that provide food and shelter for endangered animals such as Antillean manatees and green sea turtles. Coastal lagoons and mangrove wetlands give way to an upland forest that serves as a central habitat for wildlife such as the endangered brown pelican.

Derived from the Spanish word bieque, meaning "small island," the 21-mile-long stretch of land has made a big name for itself over the past decade, drawing the attention of thousands of activists, including Robert F. Kennedy Jr., who came to its aid in the early 2000s to save the refuge from ecological ruin. Since the Navy officially vacated, trendy spas, restaurants, and resorts have emerged on its shores—particularly in and around the gateway city of Esperanza. But factoring in the wildlife refuge, the island offers tropical vacation activities without the crowds of its Caribbean neighbors.

Within the refuge, subtropical forests grow out of the limestone bedrock, promoting the growth of small-leafed vegetation, cacti, and exquisite orchids, while the higher hills boast tall gumbo trees and teyer palms. Wild horses roam the grasslands, green turtles bury their eggs in the warm coral sands, and 14 species of marine birds nest in the lagoons. The 170 species of migratory and resident birds include the endemic Puerto Rican flycatcher, adelaide's warbler, and Puerto Rican woodpecker. The U.S. Fish and Wildlife Service offers guided walks, exhibits, and workshops for students and visitors while simultaneously promoting wildlife rehabilitation and restoration. Multiple day hikes award the more independent with panoramic views of the surrounding refuge. For views of the manatees, blue whales, and dolphins, depart from downtown Esperanza by the western edge of Sun Bay, following the land bridge to Cayo de Tierra. Or head out on a sea kayak and drop in to snorkel over the refuge's healthy coral reef. Beachcombers, meanwhile, can head to any of the refuge's pristine beaches. Highlights include the calm turquoise waters of 1.5-mile-long Blue Beach, the more rocky and remote Punta Vaca on the southwestern coast, and Green Beach on the western side—a perfect spot for both snorkeling and watching the sunset.

Because camping isn't permitted within the refuge, Esperanza will most likely serve as home base. The town adds more restaurants each year, many of which offer delightful outdoor dining, fresh seafood, and tropical mixed drinks in true Caribbean fashion. The town's surprisingly strong art scene specializes in pastoral landscapes, ranging from the contemporary graphics shown at Deda Galeria de Arte to the coastal scenes produced by Siddhia Hutchinson's Art Gallery and Design Studio. The Saturday market sells jewelry, clothing, and organic produce by the Esperanza Pier. Sip on rum-spiked coffee or grab a spicy shrimp kebob from a food cart as you peruse the displays. Historic ruins are buried beneath bougainvillea vines at Central Playa Grande, just one of the many 19th-century sugar plantations that once covered the island during Spanish reign. Jump on a tour lead by the Vieques Conservation and Historical Trust or embrace your inner Indiana Jones and explore on horseback. Fishermen can catch their own bonefish, permit, or tarpon during a three- to four-hour spin-casting fishing tour via kayak. Embracing its naval past, Club Tumby sports bar and grill has turned an old ammo bunker into a club that offers popular Caribbean and Hispanic beats to locals and visitors alike. Camping facilities exist in Sun Bay, or follow the newly paved roads to Bravos de Boston and sip sundowners from the seaside pool at La Lanchita Guest House.

Of course, no visit to the island is complete without visiting Mosquito Bay on the Atlantic side. The healthiest bioluminescent bay in the world, "Bio Bay" is filled with 720,000 bioluminescent organisms per gallon of water. On cloudy, moonless nights, the bay radiates an electric blue light whenever the water is agitated. It's a sight best viewed through the translucent kayaks for rent from Vieques Adventure Company.