The Lighthouse of Alexandria had three tiers. Also called the Pharos, it was built on the island of Pharos beside Alexandria in Ptolemaic Egypt during the third century BC, probably under Ptolemy II Philadelphus.
The tower narrowed as it rose. Its lower section was square, the middle section octagonal, and the upper section circular. This distinctive three-part design is described in later accounts and is supported by archaeological evidence and depictions on ancient coins.
The lighthouse guided ships toward Alexandria’s busy harbor, where low coastlines, shoals, and reefs made navigation difficult. A fire burned near the summit, and a reflective device may have helped project its glow by day or night. Its exact height is uncertain, but estimates generally place it above 100 meters.
A common mix-up is confusing tiers with internal floors or rooms. The lighthouse contained many interior spaces, but its main architectural form consisted of three tapering tiers. Earthquakes damaged it over centuries, and its remaining stones were eventually reused in the Citadel of Qaitbay.