Turn up the chill this winter island-hopping the best of The Caribbean. In Puerto Plata, uncover the local history at the 16th century Fortaleza San Felipe or embark on an off-roading adventure through lush jungle to swim in cascading mountain pools. Then snorkel among colorful tropical fish and green sea turtles in St. Thomas at Turtle Cove. Shake things up in San Juan on a guided tour that includes custom cocktails, culinary treats and historic sites.