Southern Vietnam is a region with a hot, tropical climate, consisting of the Mekong delta to the south and mountainous regions to the north. The central region was ruled by the Champa empire between the 7th and 19th centuries, while the Mekong delta region was originally part of the Khmer empire and later was annexed by Vietnam.
Near the Mekong delta lies Saigon, officially known as Ho Chi Minh city (HCM), the largest and most important city of Vietnam with over 6 million inhabitants. 80km to the northwest of Saigon is the town of Tay Ninh, the centre of the Cao Dai faith.