Cherbourg has the second largest artificial harbour in the world, with an area of 1,500 hectares. Begun in 1783, under the reign of Louis XVI who will come to Cherbourg to see the construction site, the central dike will be completed in 1853. In 1860, under the leadership of Emperor Napoleon III, it was endowed with three forts. These structures, which have evolved over time, are owned and maintained by the National Navy.