The ancient history of Afghanistan, also referred to as the pre-Islamic period of Afghanistan, dates back to the prehistoric era and the Helmand civilization around 3300–2350 BCE. Archaeological exploration began in Afghanistan in earnest after World War II and proceeded until the late 1970s during the Soviet–Afghan War. Archaeologists and historians suggest that humans were living in Afghanistan at least 50,000 years ago, and that farming communities of the region were among the earliest in the world. Urbanized culture has existed in the land from between 3000 and 2000 BC. Artifacts typical of the Paleolithic, Mesolithic, Neolithic, Bronze, and Iron ages have been found inside Afghanistan.