Dan Snow experiences what New York was like at the height of the Industrial Revolution. Millions fled to escape the persecution, poverty and famine of 19th-century Europe, only to be confronted by living conditions worse than those they had left behind. He explores the overcrowded slums of Lower Manhattan, which were a breeding ground for cholera and typhoid, and has a go at cooking using clothes dye and floor cleaner - ingredients that were added to meals to disguise the smell of spoiled meat. He also discovers how certain feats of engineering transformed not only the city, but the world.