TIJUANA, Mexico — A bus carrying farm workers and their families home has plunged off a cliff in northern Mexico, killing 14 people. A police report says the bus was traveling along a treacherously winding stretch of highway when it plummeted off the 40-meter (130-foot) cliff halfway between the border cities of Tijuana and Mexicali. The workers were returning home to Sinaloa state from farms in Baja California state.