Harrods in Knightsbridge is a great sightseeing todo

Harrods in Knightsbridge (closest to Knightsbridge Tube) is awesome. It is massive for a start and it goes over alot of floors. You can walk among some really high end fashion and home furnishings. They have an amazing Food Hall on the ground floor which you can sample stuff from and buy bits here and there. They have so much food it is overwhelming, you can do your grocery shopping there or just shop by food style and country. They have a kids section on the higher floors, and on the top there is an electronics/hi-fi area and a CD/DVD/Book shop.

The Harrods building itself is beautiful and if you are lucky you might spot a celebrity or two. Last time I was there Posh Spice was also.

In the basement there is a tribute to Princess Diana and Dodi Al-Fayed. This is fund at the bottom of the Egyptian stairway which you cannot miss.

I would say allow a good couple of hours to explore this place if you really want to get the most out of it.