LONDON (AP) — The British Museum is planning its first major exhibition of underwater archaeology with a showing of artifacts from two of Egypt's "sunken cities." Officials said Monday that the six-month exhibit set to open in May will contain 300 objects from cities that have been submerged at the mouth of the Nile River for more than 1,000 years. The museum said the items have been unearthed off the coast of Alexandria in Egypt over the past 20 years. Earlier attempts to find articles from the cities of Thonis-Heracleion and Canopus, which were swallowed by the sea, had failed. Officials said the finds at the two cities are transforming the understanding of the relationship between ancient Egypt and ancient Greece. The exhibit will be supplemented with other objects from the river delta. Join the conversation about this story »