London Bridge is not really a special bridge, at least not seen from the outside. The goal of the architects wasn’t to make it very special either, but it was to create a bridge that would help the traffic in London, and that could carry heavy transportation.
On the location where the London Bridge is located, it has almost always been bridges. The first bridge was constructed here around 50 AD, and after that several bridges were built here.
The current bridge was opened by Queen Elisabeth in 1973. A museum will hopefully open in 2012 presenting the history of the bridge.
Metro: London Bridge