According to the Free Dictionary,
A place or situation referred to as a shambles is
usually a mess, but it is no longer always the bloody mess it once was.
The history of the word begins innocently enough with the Latin word scamnum, "a stool or bench serving as a seat, step, or support for the feet, for example." The diminutive scamillum, "low stool," was borrowed by speakers of Old English as sceamol, "stool, bench, table." Old English sceamol became Middle English shamel,
which developed the specific sense in the singular and plural of "a
place where meat is butchered and sold." The Middle English compound shamelhouse meant "slaughterhouse," a sense that the plural shambles
developed (first recorded in 1548) along with the figurative sense "a
place or scene of bloodshed" (first recorded in 1593). Our current,
more generalized meaning, "a scene or condition of disorder," is first
recorded in 1926.
The photo above shows the York Shambles today. It was identified as a butchers' row or shambles as far back as the Domesday Book. Via ORB