Cwm Ivy marsh (on the North Gower coast in Wales) was claimed from the sea back in the 17th century. Since then, it has mainly been an area of farmland and freshwater marsh.
However, in August 2014, the sea took it back when a breach opened up in the seawall. At that time there were discussions about the best approach to take for its ongoing management (including suggestions about creating additional breaches in the embankment). However, the preferred option was to largely leave it alone ('no active intervention') and let the site evolve on its own.
There has been some on site management and improvement though including adding bird hides or potential osprey nests for example.
The site has become a diverse transitional marine to freshwater habitat and an excellent example of how these realigned sites rapidly evolve. This evolution has been captured by monitoring work and in a series of videos by the National Trust.
FOR VIDEOS - SEE LINK ON THIS PAGE AS WELL NATIONAL TRUST WEBSITE BELOW.