In pre-European times, the Fijian islanders cooked food in bamboo strips on an open fire but, with increased trade with the Tongans, the underground oven or lovo was adopted. To make a lovo, a hole is dug in the soil, laid with wood over which black volcanic stones are placed. A fire is lit, the stones are heated and the food, wrapped carefully in banana leaves or tin foil, is placed on top. The main constituents are usually a whole pig at the bottom with dalo, yam, chicken, fish and palusami laid on top in order to give each the correct amount of cooking. The hole is covered with coconut leaves with soil spread on top sealing in the heat and cooking the food slowly (anything from an hour to five hours depending on size). Most Fijian families prepare a lovo early Sunday morning before heading to church so it is ready for eating at lunch. Lovos also form the heart of ceremonial feasting at weddings, funerals and any other communal gathering.