In order to protect the valuable shipping business in Alexandria, Pharaoh Ptolemy Soter in 290 B.C.E. conceived of the need for a way to protect ships around the dangerous Egyptian coast, as well as to lead ship there to further trade. An ambitious project, the architect Sostratus and workers at the Library of Alexandria worked out the details of the forty story edifice. The Lighthouse at Alexandria was built to reflect sunlight with a massive mirror during the day, and used a giant fire at night. Placed on Pharos (or Pharaoh's Island), it was dedicated to Poseidon (whose statue topped the Lighthouse) as well as to Ptolemy Soter and his wife Berenice by their son Ptolemy Philadelphius, who completed it upon his father's death.
A fantastic structure sheathed in white marble, it was also sturdy: it survived wars and several major earthquakes, finally falling into total disuse by 1349 C.E., according to the traveler Ibn Battuta, as the Islamic rulers moved Egypt's capital to Cairo. The tower of the Lighthouse at Alexandria was finally brought down in 1480 C.E. by Sultan Qaitbay, who used the stone and marble of the tower to increase Alexandria's defenses by building a fort with them. 
