Which wonder was a lighthouse built on the island of Pharos in Egypt?

The wonder that was a lighthouse built on the island of Pharos in Egypt is the Lighthouse of Alexandria.

Also called the Pharos of Alexandria, the lighthouse was built by the Ptolemaic Kingdom in the 3rd century BC. Construction began after Alexandria was founded by Alexander the Great in 332 BC and was completed during the reign of Ptolemy II Philadelphus, between about 284 and 246 BC. It guided ships toward Alexandria's harbour, whose flat coastline and submerged hazards made navigation difficult.

Ancient descriptions suggest a monumental tower with three main levels: a square lower section, an octagonal middle section, and a cylindrical upper section. Its total height is often estimated at more than 100 metres. A fire produced light at night, while a reflective surface may have helped amplify sunlight during the day.

The Pharos was one of the Seven Wonders of the Ancient World, not one of the New 7 Wonders. Earthquakes damaged it repeatedly, especially in 956, 1303, and 1323. By 1480, its remaining stones had been reused in the Citadel of Qaitbay. Underwater archaeological remains are still found in Alexandria's Eastern Harbour.