Traditionally associated with the biblical patriarch Abraham, Tel Beersheva is a mound of ruins created by nine successive settlements. Archaeologists have uncovered two-thirds of a city dating from the early Israelite period (10th century BC). Because of the site's significance for the study of biblical-period urban planning, UNESCO has recognized Tel Beersheva as a World Heritage Site. At the top of the tell is the only planned Israelite city uncovered in its entirety, which includes sophisticated waterworks and a fascinating reconstructed horned altar. A fine example of a circular layout typical of the Iron Age, the city is believed to have been destroyed around 706 BC by Sennacherib of Assyria. At the northeastern end, outside the 3,000-year-old city gate, is a huge well (the deepest in Israel) which apparently once reached groundwater 90 feet below. This ancient well served the city from its earliest times, and scholars speculate that it could be the well that is documented in the Bible as Abraham's Well (Genesis 21:22–32). The observation tower is rather ugly, but it does afford beautiful views.