I have been here for a few months and there is still so much I haven't seen. There is always something going on in the centre which is free. It is a beautiful city.
Insider Tip:Make sure you get an oyster, get a tube map from a worker at any tube station as it is very helpful. When travelling around the centre catch buses, so much nicer than the tube and you get to see a lot more, plus its cheaper. If staying at a hostel pick up the free map which has the information of a free walking tour, go on the free walking tour it is very good.