It is the task of builders to turn architects’ visualisations and ideas, as well as designers’ and traffic engineers’ plans, into a workable and functioning system. The builders are workers in various professions, including tunnel-diggers, reinforcement workers, concrete workers, operators of various machines, foremen, preparatory workers, surveyors and construction managers. All of them have been involved in the process of creating metro lines in a metropolis at the heart of Europe for more than fifty years.