The ancient Polynesians stopped making pottery over a millennium ago and instead developed an ingenious way of cooking in an underground earth oven known as an umu, ahimaa, or lovo.
First a stack of dry coconut husks is burned in a pit. Once the fire is going well, coral stones are heaped on top, and when most of the husks have burnt away the food is wrapped in banana leaves and placed on the hot stones–fish and meat below, vegetables above.
A whole pig may be cleaned, then stuffed with banana leaves and hot stones. This cooks the beast from inside out as well as outside in, and the leaves create steam.
The food is then covered with more leaves and stones, and after about 2.5 hours everything is cooked.