Cantho is a relatively large city in the heart of the Mekong Delta, in Vietnam. Cantho has a population well in excess of 1 million and is the biggest city in the Mekong Delta. Although developing fast (about 10% growth in 2004), it retains its charm as the center of a rural area, as urban development is taking place in a rather orderly manner.
The floating markets are a very lively scene, accommodating much of the goods exchange throughout the area, and can be quite freely visited on board smaller boats for about US$3/hour per boat. You may take a tour from the Ninh Kieu pier, in front of Nam Bo restaurant, where the "boat ladies" are charmingly eager to welcome you aboard.
(http://wikitravel.org/en/Cantho)