Urban poverty has been described as one of the biggest challenges facing the world in the 21st century. The figures are stark: in 1950, the number of people living in urban areas amounted to 300 million. At the start of the new century, that figure had multiplied almost ten-fold, to 2.85 billion - or almost half the world's total population. And the flow of rural migrants arriving in the world's megacities shows no signs of slowing down. With the backdrop of the growing urban slums surrounding Lima, capital city of Peru, this programme examines the enduring magnetism of big cities - and asks whether the migrants who've moved here now feel that city life is the answer to their dreams.