Twice in the Bible, Jews are commanded to affix a mezzuzah to the doorpost of their houses. There are rules about precisely when and where they should be placed, and in the doorways of which rooms they should and should not be placed. A mezzuzah is a piece of writing and for details of what is written click HERE to read the WikiPedia entry. The mezzuzah (plural mezzuzot) must be protected from the elements, and so it is covered, with a cover made of metal, glass, wood, or some other material. Typically the covers are betwen three and six inches (9 to 15cm) long.
Many of the buildings in the commercial shopping centre of Jerusalem are stone-fronted and have been through several incarnations. And unlike the mezzuzah covers in the doorways of private houses in the residential areas, many of the mezzuzahs are sunk into the stonework.
This first one is not recessed but it is polished in the middle by the countless people who have touched their fingers to it as they entered the building.
The original mezzuzah that was recessed into the stonework has been removed, and a new one screwed to the stone.
Another mezzuzah with part worn and polished by the hands of people entering the building.
And a large, modern cover.