Which ancient wonder stood in Alexandria and was one of the tallest structures of the ancient world?

The Lighthouse of Alexandria stood on the island of Pharos and was one of the tallest structures of the ancient world.

Construction is usually dated to the reign of Ptolemy I Soter and completion during the reign of Ptolemy II Philadelphus in the early 3rd century BCE. The tower guided ships into Alexandria's harbour, one of the most important ports of the Hellenistic Mediterranean.

Ancient descriptions portray a multi-level structure built from large blocks of pale stone, with a fire or reflective signal at the summit. Its exact height is uncertain, but ancient and later estimates commonly place it between about 100 and 130 metres. The name “pharos” became a general word for lighthouse in several languages.

Earthquakes damaged the lighthouse repeatedly, and its remaining ruins disappeared by the 15th century. Stones from the site were reused in the Qaitbay Citadel. Unlike the Great Pyramid, the lighthouse no longer survives above ground.