An elaborate network of canals known as khlongs gave Bangkok the nickname "Venice of the East" at a time when most transportation was by boat. Today, nearly all of the canals have been filled in and converted into streets. While many khlongs still exist with people living along them and markets often being operated along the banks, most are severely polluted. A notable khlong market is the floating market in Taling Chan district. Through downtown Bangkok runs the Khlong Saen Saeb, which has a canal boat service. The wide river Chao Phraya, flowing through the city.