Once a site of fishing and trading villages situated along the Congo River, Kinshasa is now one of the world's fastest growing megacities. It faces Brazzaville, the capital of the neighbouring Republic of the Congo; the two cities are the world's second-closest pair of capital cities (after Vatican City and Rome). The city of Kinshasa is also one of the DRC's 26 provinces. Because the administrative boundaries of the city-province cover a vast area, over 90 percent of the city-province's land is rural in nature, and the urban area occupies a small but expanding section on the western side.