[2] Grosvenor Square was one of the three or four most fashionable residential addresses in London from its construction until the Second World War, with numerous leading members of the aristocracy in residence.

Number 23 (later 26) was rebuilt in 1773–74 for the 11th Earl of Derby by Robert Adam, and is regarded as one of the architect's finest works and as a seminal example of how grandeur of effect and sophisticated planning might be achieved on a confined site.

Reserved for residents' use for much of its life, the Grade II-registered landscape[4] was, after the Second World War, made a public space for everyone's enjoyment, through the Roosevelt Memorial Act 1946 (9 & 10 Geo.

[8] In the 1920s, four of the "Bentley Boys" – Woolf Barnato, Tim Birkin, Glen Kidston and Bernard Rubin – took adjacent flats in the fashionable south-east corner of the square, where their day-long parties became something of social legend.

So common was the sight of their large, green sports cars parked ad hoc outside their flats, that for many years London cab drivers referred to the spot as "Bentley Corner".

This was a large and architecturally significant modern design by Eero Saarinen, being at the time a controversial insertion into a mainly Georgian and neo-Georgian district of London.

In 2006, the Grosvenor Square Safety Group residents association took out advertisements in The Washington Post and The Times, accusing the Metropolitan Police and local government of a "moral failure" for not closing two other roads adjacent to the embassy.

[12] In 2008, the United States Government chose a site for a new embassy in the Nine Elms area of the London Borough of Wandsworth, south of the River Thames.

Ambassador to the United Nations, Adlai Stevenson, suffered a heart attack, later dying at the old St George's Hospital at Hyde Park Corner.

[17] The poem For Katrina's Sun-Dial by Henry van Dyke was chosen for inscription on an elliptical granite block engraved with the names of the victims, underneath which is buried a piece of the steel wreckage.

The former United States Navy building at 20 Grosvenor Square was sold in 2007 for £250 million to Richard Caring, who planned to turn it into 41 residential apartments.