Lighthouse of Alexandria: one of the Seven Wonders of the Ancient World.
Commissioned in 299 BCE by king Ptolemy I Soter of Egypt, the Lighthouse of Alexandria was built by an architect named Sostratus; it was finished in 279, when Ptolemy II Philadelphus was on the throne. The monument is often called Pharos, after the island on which it was erected. It consisted of three main elements:
- A square base 56 meters high;
- An octagonal middle 28 meters high;
- A circular top of perhaps another 28 meters; the total was more than 100 meters.
Although it was originally just a high tower that made the port of Alexandria visible from far away, at some time in the first century BCE, it was converted into a real lighthouse, so that sailors could benefit from it by night as well. It was destroyed by an earthquake in 1326. The sequence (square, octagonal, circular) has inspired more recent towers.