Archaeologists from Syria and the United States have been excavating a site known as Tell Zeidan, on the borders of Syria and Turkey. This site is rare in the fact that there has been no further building or settlement in the area since the Ubaid Period (5,500 - 4,000 BCE) so the evidence found is 'clean'. The Ubaid is a largely unexplored period, with the majority of the sites so far being either very small or not accessible enough (mixed with other periods) to reveal more than a glimpse of this civilisation, where long distance trade became of greater importance and where the beginnings of a hierarchical class structure started to emerge.
     The site is of such immense importance that Guillermo Algaze, of the University of California, is quoted as saying that the site "has the potential to revolutionise current interpretations of how civilization in the Near East came about".

Source: The New York Times (5 April 2010)