The biggest floating market in the Mekong Delta, Cai Rang is 6km from Can Tho in the direction of Soc Trang. There's a bridge here that serves as a great vantage point for photography. The market is best around 6am to 7am, and it's well worth getting here early to beat the boatloads of tourists and the heat. This is a wholesale market, so look at what's tied to the long pole above the boat to see what they're selling.
Cai Rang can be seen from the road, but getting here is far more interesting by boat (US$10 to US$15). From the market area in Can Tho it takes about 45 minutes by boat to the market, or you can drive to the Cau Dau Sau boat landing (about 4km southwest of Can Tho by the Dau Sau Bridge), skipping the least interesting section of river, from where it takes only about 10 minutes to reach the market.