The Maunsell sea forts are a group of forts built during World War II. Today, they stand in the Thames estuary and are truly man-made islands that provide refuge for the local birds as well as a navigational guide for ships.
Although not all of them still stand, there are plans to conserve them and to open them up for visits.
The White Cliffs of Dover on the English coast are one of the most well known English landmarks. They can be seen from Calais and from the Channel. They hold a special value in English history.