Morocco’s the kind of place you visit once—and immediately know you’ll be back. There’s plenty to make this impression: It might be the way Marrakech, the Red City, glows as the sun rises, or how intoxicating it is to watch magicians and storytellers move in knots through Jemaa el-Fna Square as that same sun sets. The thrill of haggling for rugs and cuffs and copper trinkets inside Fez's maze-like medina could do it. Or perhaps it’s that view of Spain, clear across the Med, as you sip tea...