Sunbathing and sipping margaritas is just one of many ways to spend a vacation in Puerto Vallarta. Mexico's prettiest resort town is also one of its most diverse. Old Vallarta—El Centro and the Zona Romántica—is a goldmine of quirky boutiques and winding cobblestone streets. In Marina Vallarta, shopping centers and deluxe hotels spread around the city's yacht marina. And from Costalegre to the Riviera Nayarit, miles of sandy beaches and scores of stellar restaurants and lively nightclubs, surrounded by historic mountain towns, keep visitors returning again and again.