CARIBBEAN: For decades it was believed that the Caribbean islands were settled in a stepping-stone fashion by Amerindians migrating from South America. After reviewing 2,500 radiocarbon dates from 55 islands, researchers are now telling a different story. While Trinidad, the closest island to South America, was the first to be settled, 7,000 years ago, humans didn’t simply jump to the next island. Instead, they rode currents north across open sea to Puerto Rico, Cuba, and Hispaniola, before journeying back southward thousands of years later via a chain of smaller islands.