Final preparations are made ahead of the 69,000 lights finally being switched on, and electricians and abseilers are working flat out to finish on time. However, the installation on Millennium Bridge is proving difficult. The American artist behind the project finally arrives in Londin and begins the process of making his vision a reality. Charlie Luxton explores Tower Bridge and looks at the history of art inspired by the Thames, joining artist Stephen Wiltshire to paint a view famously captured by Monet.