The Neolithic 1 (PPNA) period began roughly 10,000 years ago in the Levant. A temple area in southeastern Turkey at Göbekli Tepe dated around 9,500 BC may be regarded as the beginning of the period. This site was developed by nomadic hunter-gatherer tribes, evidenced by the lack of permanent housing in the vicinity and may be the oldest known human-made place of worship. At least seven stone circles, covering 25 acres (10 ha), contain limestone pillars carved with animals, insects, and birds. Stone tools were used by perhaps as many as hundreds of people to create the pillars, which might have supported roofs. Other early PPNA sites dating to around 9,500 to 9,000 BCE have been found in Jericho, Israel (notably Ain Mallaha, Nahal Oren, and Kfar HaHoresh), Gilgal in the Jordan Valley, and Byblos, Lebanon. The start of Neolithic 1 overlaps the Tahunian and Heavy Neolithic periods to some degree.[citation needed]