A Sea Wall

This is the view of the light house at the end of a very long sea wall. It looks like it may be connected to land at the other end, but I think that land is another island. At the other end of the wall is a red lighthouse, and why would they put a light house there if it was connected to land?

I am not sure of the purpose of the wall is. Obviously it serves as a breaker to the waves coming in from the East China Sea, but there could be another purpose. It is one of the longest sea walls that I have seen.