The city’s geography is defined by rivers and canals, of which the largest is Saigon River. As the largest financial centre in Vietnam, Ho Chi Minh City has the largest gross regional domestic product out of all Vietnam provinces and municipalities,^[8] contributing around a quarter of the country’s total GDP.^[9] Ho Chi Minh City’s metropolitan area is ASEAN’s 5th largest economy, also the biggest outside an ASEAN country capital.