David Dimbleby completes his journey through Britain, discovering how the nation's history has shaped its buildings, in the south of England, exploring its dramatic transformation in the 20th century. Modern technology opened up new worlds to ordinary people, changing the way they worked, lived and played. He begins in Metroland, part of the suburban explosion of the 1920s and 1930s, with its 'Tudorbethan' houses and sumptuous cinemas like Moorish palaces, traces the arrival of the bold new modern style at a glorious public swimming pool on the south coast, and sees what effect the war had on what we built – from much-loved prefabs to high-rise blocks. And he visits the new temples of money in the City of London – breathtaking towers of steel and glass – and asks how many of them will still be there one hundred years from now.