In the innocuous building of the casting hall lies the centrepiece of the Metallurgic Park. It is the blast furnace built in 1834 and modernised in 1839. Its dimensions impose themselves on the visitor. Here, men seem insignificant and yet it is they who will tame the incandescent material. “Keeping on working, forging red steel with their golden hands”: these words, sung by Bernard Lavilliers in homage to the steel workers, were not in vain during the great era of the metallurgy in Dommartin-le-Franc (Haute-Marne). The park brings back to life the Blaise Valley factory, one of the most active production sites of the 19th century.