The famous lighthouse in Alexandria during Cleopatra's reign was the Pharos.
The Lighthouse of Alexandria, commonly called the Pharos, stood on the island of Pharos beside Alexandria's harbor. It was built by the Ptolemaic Kingdom centuries before Cleopatra, beginning under Ptolemy I Soter and being completed during the reign of his son, Ptolemy II Philadelphus, in the third century BC. Cleopatra inherited the monument as part of the Ptolemaic capital's landscape.
The tower guided ships toward Alexandria's dangerous coastline, where shallow waters and submerged reefs made navigation difficult. Ancient descriptions and later reconstructions portray it as a massive structure with a square lower section, an octagonal middle level, and a cylindrical upper stage containing the light. It may have stood more than 100 meters tall.
Pharos was one of the Seven Wonders of the Ancient World and gave its name to the word for lighthouse in several modern languages, including French phare and Spanish faro. It was damaged by earthquakes over many centuries and its remaining stones were eventually reused in the Citadel of Qaitbay. The Mausoleum at Halicarnassus, another Wonder, is a different monument.