There are few meals more simple yet satisfying than fresh prawns in their shells, or perhaps marinated in garlic and chilli, thrown onto a barbecue and cooked until sweet and tender. Prawns are crustaceans found in waters all over the world. While they are called prawns in most English-speaking countries, they are referred to as shrimp in North and South America. Prawns vary in size and colour but they all become opaque and turn pink once cooked.