On our recent trip to Rye harbour, we saw the Martello Tower which stands at the entrance to the nature reserve. This tower was built in the early 1800s as part of the defences against invasion by Napoleonic France. The low-lying coast around Rye would have made a perfect landing spot, so ten of these towers were created on the surrounding land as part of a broader scheme to protect potential landing sites along the southern coast of England. In all 103 such towers were constructed.
The solid Towers surrounded by a moat had a flat roof which would have had a large cannon (as seen in the example from Seaford) capable of firing on any troops of ships trying to land. They were entered via a drawbridge which could be withdrawn in the event of a landing by enemy forces. No invasion ever materialised and so they were never put to the test. The Towers were later converted to watchtowers where Coastguards kept watch for smugglers as the areas of Rye and Romney marsh were favoured landing spots for Smugglers coming across the channel from France (Boulogne is only 30 miles away). They were forced into action again during the Second World War when a heavy machine gun was mounted on the roof. However, by this time, the Tower was some 3/4 mile from the coast due to the deposition of shingle over the preceding 140 years and the remains of more modern coastal defences can be found nearer to the modern coastline.