Westminster Hall, built in the 11the century, is the oldest part of the 
complex.  A precursor to cathedral design and one of the first examples 
of architects figuring out how to build big, it was the largest enclosed 
building in Europe at the time.  In its early days, the hall had 
semi-permanent rooms and shops (which would be removed when a big trial 
or something had to take place).  <br/>There's stained glass at the end 
of the hall, but it's washed out in this picture.