Rob uncovers the story of the two Waterloo Bridges, both once hailed as bridges of the future. He discovers the original Waterloo Bridge was an icon of the Industrial Revolution, built using the latest technology to cater for the incredible growth of London. But this bridge - dubbed the finest in the world - was too expensive a crossing for the impoverished inhabitants of London, and fell into disrepair. Its replacement, the current bridge, symbolised the modern world. Rob discovers the astonishing story behind this bridge - including its war-time forgotten female labour force. Last in the series.