Historians believe fire first appeared in the world approximately 1 million years ago when inhabitants of Africa created fires for cooking food. The use of fires remained within the confines of Africa's borders for approximately 40,000 years after initial use. Humans built early fires outdoors, usually in large pits, from wood, which proved readily available, easy to transport and quick to ignite.
Humans eventually left Africa, approximately 60,000 years ago, and brought fires with them. They continued using fires primarily for cooking and heating food. During the Ice Age, however, humans found use for fires as indoor heating mechanisms. They moved fires indoors, placing them in designated spaces within their caves to create warmth safely. Around 6000 B.C., classified by historians as the Stone Age, humans transitioned from living in caves to establishing more permanent settlements in the form of villages. Houses replaced caves as residences. Wood, once an abundant fire material, became scarcer. Humans invented stoves and ovens, which replaced fires, for cooking and heating. Around that time, people harnessed energy from fires to make goods and products like pottery. Around 4000 B.C., people discovered the flammable material of charcoal. Charcoal proved abundant, as wood once was, and ignited fires around the world. Charcoal fires served the same purposes of making food and producing heat. They burned hotter than wood fires, enabling melting of iron and metals.