Which ancient wonder was completed under Ptolemy II Philadelphus?

The Lighthouse of Alexandria was the ancient wonder completed under Ptolemy II Philadelphus.

The tower belonged to the Ptolemaic building program in Egypt. Ptolemy I Soter initiated the project after establishing the dynasty that ruled Egypt following Alexander the Great’s death. His successor, Ptolemy II Philadelphus, completed the lighthouse in the third century BC, probably early in his reign.

Its placement on Pharos made the structure both a navigational aid and a visual statement at the entrance to Alexandria’s harbour. Ancient writers treated it as an engineering marvel, and its design is generally reconstructed as a three-part tower crowned by a fire or beacon.

The completion date is often given broadly because ancient sources do not provide a universally accepted exact year. This wonder is sometimes confused with the city’s famous library, but the Library of Alexandria was a separate institution. Both belonged to the same extraordinary intellectual and architectural centre.