The nondescript river town of Chau Doc is home to one of Vietnam’s less likely attractions, Islam. It’s an easy sell for tourists who are surprised to find a Muslim village on the Hau river, a wide brown-watered branch of the Mekong often depicted in Vietnam war film scenes of patrol boats fading into a jungle sunset. This is also home to the Cham, one of oldest, most idiosyncratic Muslim communities in Asia.