The green area on the map is Hyde Park. Most of the Embassies surround this park and it is just a short walk from Harrods.
The colored arrows point to key locations:
Red - Harrods
Blue - Hyde Park Corner
Yellow - Speakers Corner
Purple - Marble Arch
Black - USA Embassy
Click the forward button for more of the tour.
An Index of key sights, stops, B&B's, food and general recommendations is provided at INDEX.