Vietnam's most famous dish is probably pho, but that is merely a drop in the country's noodle-soup ocean. For a bowl crammed with colours look out for bún rieu. Bún means noodles, while rieu refers to a crab-based broth blended with tomatoes. The noodles are always fine and round. This particular bowl is made room for chewy chunks of pork, deep-fried tofu cakes, a spoon of chilli paste and slices of pickled garlic.