The site of the old city of Pompeii is huge, and the amount that has survived is really impressive. Along the streets there are these stepping stones, presumably allowing people to cross without treading in the garbage of the street itself. These streets were also used by chariots, and if you look carefully you will see there are ruts between the stones. This is where the standards come in. The guides will twell you that each chariot was built with a standard distance between the wheels, corresponding to the standard gaps between the stones. Of course we all believed him, but it is in fact a myth, and measurements within Pompeii itself reveal several different distances between the ruts. Unfortunately I did not look this up until I was writing the blog post, which was a bit silly. So, to make up for it here is some of the wall decoration that was still intact on the site.