Big Ben & Houses of Parliament
We start at Westminster Underground. When you come out of the main exit, perhaps London's most famous icon, Big Ben towers above you. You are standing at the western end of Westminster Bridge. Cross over the busy main road in front of you, using the official crossing or underpass.
Big Ben is part of the Palace of Westminster originally started in 1020. The palace was burnt down in 1834, so the Gothic architecture you see today is comparatively recent.
The palace houses both of the the UK's ruling bodies, the Houses of Parliament and the House of Lords.
When parliament is sitting after dark, a light shines from the top of Big Ben's tower. For obvious reasons, security is out in force.
It is possible to arrange tours, visit debates in the chamber, even climb Big Ben's tower. However don't expect just to turn up and walk in. For UK residents going through their own MP it is much easier than for foreign visitors who can only tour during the summer opening with tickets purchased in advance.
Walk along the eastern boundary of Parliament Square heading south with Westminster Palace on your left.
On the green area in the centre of Parliament Square there are normally protesters of one sort or another with placards and sometimes tents.
This central area is not solid earth, if a vehicle strayed onto the green there is a chance it may fall into the London Underground line below.