The Acropolis of Athens is the best known acropolis (high city, The "Sacred Rock") in the world. Although there are many other acropolises in Greece, the significance of the Acropolis of Athens is such that it is commonly known as The Acropolis without qualification. The Acropolis was formally proclaimed as the pre-eminent monument on the European Cultural Heritage list of monuments on 26 March 2007. The Acropolis is a flat-topped rock which rises above sea level in the city of Athens. It was also known as Cecropia, after the legendary serpent-man, Kekrops or Cecrops, the first Athenian king.