Between 1870 and 1914, the Menier factory in Noisiel was the largest chocolate factory in the world. But it was also, and above all, a pioneering factory in terms of architectural innovation. Its iron and then concrete architecture symbolized the company's power and modernity. Its three major buildings - the Saulnier Mill, the world's first all-steel structure, the Eiffel Hall and the Cathedral - tell the story of the golden age of industrial architecture.