The Lighthouse of Alexandria was a tower built in the 3rd century BC on the island of Pharos in Alexandria, Egypt, to serve as that port's landmark, and later, its lighthouse. With a height variously estimated at between 115 and 135 m it was identified as one of the Seven Wonders of the Ancient World by Antipater of Sidon. It may have been the world's third tallest building after the two Great Pyramids for its entire life.