Can you plan a walk of London by applying a pair of compasses to the map? Of course you can.
Obviously, London won't bend to perfect curves, putting monuments, building sites and the zoo in the way but a pair of intrepid, mildly obsessive, walkers have done it many times always trying to improve the circular route taken. They conclude "it is fascinating to observe what happens when an abstract geometrical shape is superimposed on an urban landscape".
The London Circle Walk sets off again on Sunday 30 September at 10am sharp from Tower Bridge. It can take anything between 6-9 hours depending on the group's pace, stops for refreshment etc. If you'd like to join this orbital perambulation contact details are at the bottom of this splendid blog post about the genesis of the walk.
If you can't do 30 September, watch this excellent video redux and pretend you've done it.
The London Circle Walk was devised by Tim Wilson and Michael Brunström.