Troy or Ilion was an ancient city located in present-day Hisarlık, Turkey. The place was first settled around 3600 BC and grew into a small fortified city around 3000 BC. During its four thousand years of existence, Troy was repeatedly destroyed and rebuilt. As a result, the archeological site that has been left is divided into nine layers, each corresponding to a city built on the ruins of the previous. Archaeologists refer to these layers using Roman numerals.