This is the Serpentine lake in Hyde Park,you can swim in it from the area by the cafe.This view is towards central London,the large building on the skyline is one of the London Hiltons from the bar at the top a good into Buckingham Palace gardens can be obtained.The Diana water feature is to the right approx behind the tea room. Diana lived about half a mile behind ,still in the park ,in Kensington Palace.It is open to the public but the actual suites she occupied have been rearanged and do not form a continuous group of rooms anymore.