Archaeological exploration done in the 20th century suggests that the geographical area of Afghanistan has been closely connected by culture and trade with its neighbors to the east, west, and north. Artifacts typical of the Paleolithic, Mesolithic, Neolithic, Bronze, and Iron Ages have been found in Afghanistan. Urban civilization is believed to have begun as early as 3000 BCE, and the early city of Mundigak (near Kandahar in the south of the country) was a center of the Helmand culture. More recent findings established that the Indus Valley Civilization stretched up towards modern-day Afghanistan, making the ancient civilization today part of Pakistan, Afghanistan, and India. In more detail, it extended from what today is northwest Pakistan to northwest India and northeast Afghanistan. An Indus Valley site has been found on the Oxus River at Shortugai in northern Afghanistan. There are several smaller IVC colonies to be found in Afghanistan as well. An Indus Valley site has been found on the Oxus River at Shortugai in northern Afghanistan, shows Afghanistan to have been a part of Indus Valley Civilization.