Historically, Hyde Park Corner was the roadway running between Hyde Park and Green Park, linking Knightsbridge to Piccadilly. Chronic congestion from horse-drawn traffic prompted an 1882 widening scheme that sliced off the western tip of Green Park. A far larger redesign followed between 1960 and 1962, when planners carved swathes from both the western edge of Green Park and the northwestern corner of the Buckingham Palace Garden to install a modern roundabout and underpass, creating the grassy traffic island that maps now label Hyde Park Corner. - AsNotedIn