Northern Mesopotamia evolved independently from the south during the Late Chalcolithic / early and middle Northern Uruk (4000–3500 BC). This period was characterized by a strong emphasis on holy sites, among which, the Eye Temple was the most important in Tell Brak. The building containing "Eyes" idols in area "TW" was wood paneled, whose main room had been lined with wooden panels. The building also contained the earliest known semi columned facade, which is a character that will be associated with temples in later periods.