The capital's planned new river crossing faces opposition at every turn. Why has it always been so hard to find new ways across the Thames in East London?
The strangest part of London's planned inner Motorway Box - not just because it's nothing like the other three sides, but also because it actually got built.
During the 1960s the UK developed some of the most sophisticated - and strange - electronic variable message signs anywhere in the world. How? And, just as importantly... why?