The Fourth Plinth is in the north-west of Trafalgar Square, in central London. Built in 1841, it was originally intended for an equestrian statue but has been vacant for many years.
It is now the location for specially commissioned artworks.
And this summer Anthony Gromley, the sculptor, has created it into a living monument - One & Other. For 24 hours a day, for one hour each, from July 6 2009, the Fourth Plinth will have different people who were chosen randomly from applications, to stand on it. The occupant can use the space and time for whatever he chooses as long as it is legal.