Part of the old harbour wall shows in the sea at the back. The harbour walls were constructed on an underwater earth fault (geological surveys were not done, before building started, in 50 BC), which shifted at some time and most of the walls are now under water.
There were no natural walls to build on, so the construction of these walls was also quite a feat at the time. Poor cheap labour, probably.
May your dreams for the new year not be built on invisible faults, so that it may prove to be a profitable and joyous 2016.