Walls are to built to keep people out, or to keep things in. A newly constructed wall may seem to be just the addition you wanted. Given time all walls seem to crack and crumble, either from within or without. Some are constructed on unstable ground and need frequently amended. Some are built for all the wrong reasons and some for survival. Some walls are the only protection from invasion in the cold, dark, night. These walls are generally the toughest type made. Built to withstand the thrown stones and motor fire. Yet stand on in quiet servitude.
Some walls are as old as all of humanity. Erected to fight an ancient battle, that long since lost meaning or bearing. Yet the walls of their ancient fortresses remain. Standing still against the sun and storm alike. Holding firm despite their cracks. They stand against the rain and cold, as they have always done since time unknown.
Some walls are made a prison. To hold within that which is deemed unbearable. The pent up place where the unwanted are stuffed, til claustrophobia sets in. The walls of this dungeon are deep enough to stifle all the cries.