Puerto Rico is the easternmost island in the Greater Antilles chain and an unincorporated territory of the United States. It had been inhabited for hundreds of years by the indigenous Taino people before Christopher Columbus claimed the island for Spain in 1493. Spanish conquistadors used enslaved Tainos and Africans to tend their large sugar cane plantations, as well as help build a fortified governor’s palace (La Fortaleza) and two massive forts to protect San Juan Bay from repeated attacks. After the Spanish-American War of 1898, Spain ceded Puerto Rico to the U.S.; in 1917, residents were granted U.S. citizenship. Today, the “Island of Enchantment” dazzles with its vibrant culture, Old San Juan — a colonial charmer with leafy plazas and mix of Gothic, Renaissance and Baroque architecture — and the UNESCO World Heritage-designated La Fortaleza and fortresses of San Felipe del Morro and San Cristobál. Natural wonders include a slew of gorgeous beaches, lush reserves like Caja de Muertos and El Yunque — the only tropical rainforest in the U.S. — surreal bioluminescent bays, and Cueva Ventana, a cliff-side cave with Taino petroglyphs and much-photographed “window” overlooking the Arecibo River Valley.