La Cité de la Mer, the cylindrical aquarium in northern France, is celebrating 500,000 visitors gazing into its vast glass columns, since opening 15 months ago.

Built at the port of Cherbourg in Normandy, the spiral aquarium with over 3,000 fish, has more than doubled its predicted visitor numbers of 200,000 per year.

Sited in the Grande Halle, a 9000sq metre Art Deco exhibition space, renovated as part of the refurbishment of the 19th century transatlantic port and station, La Cite de la Mer has proved such a success that Cherbourg’s hotel accommodation has reached saturation point.

The Presse de la Manche newspaper has reported that every hotel room was taken in the city last month. Visitors to La Cité de la Mer are staying in rooms in towns as far away as Caen and Bayeux, about one and a half hour’s drive from Cherbourg.

The port of Cherbourg, which welcomes more than 800,000 British visitors a year, will also launch a new exhibition on 29 July. Situated in the car ferry terminal, a series of photographs, maps and drawings will mark the opening of La Cité de la Mer and the restoration of the Grande Halle; tourism in Cherbourg and La Manche and the 60th anniversary of the D-Day landings on the west coast of the peninsula. Details: www.citedelamer.com