Britain is marking Queen Elizabeth II's 60th year on the throne with a four-day holiday weekend of ceremony, symbolism and street parties. This is only the second time in its history that the UK has celebrated the Diamond Jubilee of a monarch. The Queen, along with all the members of the royal family, will participate in a River Pageant with a flotilla of 1000 boats accompanying them down the Thames, a free concert at Buckingham Palace, a carriage procession and a Service of Thanksgiving at St Paul's Cathedral.