London Stone is a historic landmark at 111 Cannon Street in the City of London. It is an irregular block of oolitic limestone measuring 53 × 43 × 30 cm (21 × 17 × 12″), the remnant of a once much larger object that had stood for many centuries on the south side of the street.
The name “London Stone” was first recorded around the year 1100. The date and original purpose of the Stone are unknown, although it is possibly of Roman origin, and there has been interest and speculation about it since at least the 16th century. Modern claims that it was formerly an object of veneration, or has occult significance, are unsubstantiated.