At the end of your visit, will all the transfers to Gatwick airport by taxi or to other airports will be very sad, because you will want to stay in London forever. Unfortunately, it is not possible, but you can enjoy as much as the moments spent in London.
The Buckingham Palace should be the first stop. It is the Queen’s official residence in London, which has 775 rooms. This is one of the few working palace that remain until today and has a magnificent architecture. You can admire the State Rooms of the Palace during the summer months, but in the rest of the year, you can see the famous changing of the guard.