The palace of Cleopatra sunk into the sea more than 1500 years ago. Historians believe that earthquakes and tidal waves caused the downfall of Cleopatra’s palace. The ancient underwater ruins of Cleopatra are found under the Mediterranean sea off the shore of Alexandria, located on the southern coast of the Mediterranean Sea, in Egypt. Alexandria was founded by Alexander the Great in 331 BC. The city grew to become the intellectual and cultural centre of the ancient Mediterranean world. Today, with over 5 million inhabitants, Alexandria is the most populous city in the Mediterranean.