The Pearl River Delta Metropolitan Region (PRD), also known as Zhujiang Delta or Zhusanjiao, is the low-lying area surrounding the Pearl River estuary, where the Pearl River flows into the South China Sea. It is one of the most densely urbanized regions in the world. This region was also the source of much Chinese emigration from the 19th to the mid 20th centuries, including to the Western world, such as the US, Canada, Australia, Latin America, and much of Southeast Asia, where they formed many Chinatowns. Today, much of the Chinese diaspora traces their ancestry to this region. Its dominant language is Cantonese.