The passage of time.

The cattle are making use of this WW2 Pill Box, I don't know why, because it provides very little shelter.
The fear of invasion in 1939 prompted the construction of many small fortifications at strategic points along highways. The coastline near here would have been a possible landing area as it is flat and sandy. I can remember the shore being filled with wooden posts to prevent aircraft landing and also to slow down a seaborne invasion.
I have always thought that the pill box pictured above would have been destroyed with one mortar round!
All a bit "Dads Army".