The Lighthouse of Alexandria, sometimes called the Pharos of Alexandria, was a lofty tower built by the Ptolemaic Kingdom between 280 and 247BC on the coastal island of Pharos at Alexandria, Egypt for the purpose of guiding sailors into the port. With a height variously estimated at somewhere between 393 and 450 ft (120 and 140 m), it was one of the tallest man-made structures on Earth for many centuries, and was regarded as one of the Seven Wonders of the Ancient World. Badly damaged by three earthquakes between 956 and 1323, it then became an abandoned ruin. It was the third longest surviving ancient wonder (after the Mausoleum at Halicarnassus and the still extant Great Pyramid of Giza) until in 1480 the last of its remnant stones were used to build the Citadel of Qaitbay on the site. In 1994, French archeologists discovered some remains of the lighthouse on the floor of Alexandria's Eastern Harbour.