Fire has provided humans with heat, protection, fuel, and the ability to cook food. All of these advantages contributed to the development of mankind, for it changed the way humans moved about the globe, altered diet and behavior, and led to further cultural and technological innovations.
While there are various myths and legends surrounding the discovery of fire - such as Prometheus stealing it from the gods and some animal bringing it from some evil being - the earliest evidence of the control of fire by a member of the Homo genus dates to approximately 1.7-0.2 million years ago. Flint blades that had been burnt in fire about 300,000 years ago were found in Morocco close to fossils of early Homo sapiens. The widespread control of fire by modern humans appears to date to 125,000 years ago.
The discovery of fire and the ability to control was a process that is not known definitively. First, ancient beings would have used and conserved fires that occurred from natural instances such as lightning strikes, forest fires, meteor impacts, etc. Ancient man used animal dung and other slow-burning substances to maintain fires. Following the opportunistic use of naturally-occurring fires, Homo erectus is believed to have founded its controlled use during the Early Stone Age.
An Oldowan hominid site that dates to 1.6 million years ago in Kenya, Africa contains the earliest evidence of fire control by humans - oxidized earth patches that are several centimeters deep. Other sites in Africa contain evidence of fire, including 1.4 million-year-old burned clay clasts found in central Kenya. Outside of Africa, the earliest evidence of fire control comes from a Lower Paleolithic site in Israel; charred pieces of wood and seeds were found at a site believed to be about 790,000 years old. Similar evidence dating to a similar time was also found in China and the UK. There are conflicting opinions about the exact timeline and the precise point at which man had true control of fire, but it is generally agreed that it dates to somewhere around 400,000-800,000 years ago.
Due to the control of fire, humans could inhabit cooler places, cook food, stay up later, and wake up earlier. These changes in human behavior took place approximately 800,000 years ago. Homo erectus evolved to have smaller mouths, teeth, and digestive systems which suggests that cooked food, being easier to digest, led to these changes. Hearths, in which fires could be started and maintained for cooking and other purposes, began to be constructed about 200,000-400,000 years ago. Hearths allowed humans to stay in place longer - even permanently - as fire provided heat, protection, and cooked food. Over time, humans learned the best fuel for fire and started to use fire for making tools and pottery, fueling machines, and eventually, for their leisure.