If you want a tour around London - take the Ducktours. It's an amazing and unique experience to see Central London from the land and the river... The guide we got was brilliant and funny :)
Arrive late in order to get a good seat, making sure you mob around the person running it when they arrive. We arrived over 30 mins before, and was sat last as she went to the back of the queue!
8 August: DUKWS amphibious vehicles, which previously served in the armed forces, now act as tour buses. Around 21,000 DUKWS were built, and were first used during the D-Day landings in Normandy.
The slipway next to the MI6 building is where Duck tours launch into the river. These distinctive yellow amphibious lorries were designed in WW2 and used for the D-Day landings.