The London Stone - Cannon St EC4

This rather unobtrusive grille covers an object that some consider to safeguard London itself.  Given the protective glass in front of it and my crappy photo, you can't actually see it - but let me assure you that within resides the London Stone.  Linked to all manner of legend - Brutus of Troy in 1,000 BC, an ancient stone circle on Ludgate Hill, even the mythical stone from which Excalibur was pulled by King Arthur - the stone is first referred to in 10th century Saxon records.  Once much larger and up until the 18th century, located in the middle of the road that eventually became Cannon Street in the City, the London Stone has been moved several times - including being set into the wall of St Swithin's Church.  In smaller form, but still to many containing all the mythical power that its name conveys, the stone ended up in its current home in 1962.  It really is a bit "blink and you'll miss it" , but take the time to seek it out, stop and read the plaque, crouch down and gaze at one of the most fascinating (at least in my mind) London landmarks and give thanks (just in case) to the stone that keeps us all safe.