Beneath the waters of Abukir Bay, at the edge of the north-western Nile delta, lie the submerged remains of the ancient Egyptian cities Thonis-Heracleion and Canopus. This volume, which accompanied the British Museum exhibition in 2016, describes the technical challenges that faced the underwater archaeologists; presents, with over 270 illustrations, the submerged buildings and artefacts, including jewellery and ceramics, that have been found; and discusses how these discoveries have transformed our understanding of the relationship between ancient Egypt and Greece.