Royal Military Canal
Rother, United Kingdom · built 1804
The Royal Military Canal is a canal running for 28 miles (45 km) between Seabrook near Folkestone and Cliff End near Hastings, following the old cliff line bordering Romney Marsh, which was constructed as part of British anti-invasion preparations of 1803–05 against Napoleon's planned invasion of the United Kingdom. It was designed with the intention to tactically contain the potential landing points near to Dungeness, which is approximately 20 miles from Dover and 40 miles from Calais, an area if conquered would provide a direct route to London from the coast.
Canal data from Wikidata (CC0). Summary from Wikipedia (CC BY-SA).