Knightsbridge is probably the wealthiest area in London. Streets are filled with expensive cars and Burberry clad snobs. Some of the buildings are really beautiful and there are some interesting museums as well. Harrods sells a lot of ridiculously expensive stuff from diamond collars for your cat to crystal swans that cost tens of thousands of pounds. Belgravia is an area with a lot of embassies and Victoria Station for trains to the south. I'm including these two areas in the same page, since it's difficult to draw borders for them.