In the Mekong Delta, rivers and canals criss-cross the land so completely that many villages have no roads at all - only water. Children paddle small boats to friends' houses. Markets, shops and even some schools sit on stilts above the water or on boats themselves.
The most famous part is the floating market. Just after sunrise, hundreds of wooden boats gather together on the river. Each boat is piled high with one kind of thing: pineapples, watermelons, cabbages, rice or fresh fish. Sellers tie a sample of their goods to a tall stick so buyers can spot what each boat is selling from far away.
The Mekong is sometimes called the 'rice bowl' of Vietnam, because the rich soil left behind by the river feeds enormous rice fields. Around half of all the rice grown in Vietnam comes from the delta. Fishermen also catch hundreds of kinds of fish here - the Mekong has more kinds of fish than almost any other river in the world.
The river is enormous. At the end of the rainy season, so much water flows down the Mekong every second that you could fill an Olympic swimming pool in less than a heartbeat. Whole islands appear, shift and disappear as the river changes its mind from year to year.