Which ancient wonder was built in the Egyptian port of Alexandria?

The Lighthouse of Alexandria was the ancient wonder built in the Egyptian port of Alexandria.

The structure stood on Pharos, an island guarding the harbour entrance. Alexandria was founded by Alexander the Great in 331 BC and became the capital of Ptolemaic Egypt. Its busy maritime setting made a prominent navigation tower especially valuable, while its scale also advertised the power and wealth of the Ptolemaic kingdom.

The lighthouse was begun under Ptolemy I and completed under Ptolemy II in the third century BC. Classical accounts describe a very tall tower with several stages and a beacon at the summit. Its total height is uncertain, but ancient and modern estimates often place it somewhere around 100 metres.

The lighthouse was later damaged by repeated earthquakes. Much of the surviving stone was incorporated into the Qaitbay Citadel in the fifteenth century. Underwater archaeology has recovered architectural blocks believed to have fallen from the ancient structure.