In January 1887, as soon as his project was accepted, Gustave Eiffel began the construction of the tower. Six months later, the foundations were completed and the assembly of the metal part began. The 12,000 parts were assembled and riveted in the Eiffel workshops in Levallois-Perret. They were made of puddled iron produced in the Pompey forges near Nancy. The puddling operation allowed the excess carbon still present in the cast iron to be removed. Rolled puddled iron was used to form light and robust structures. Between 150 and 300 workers put together this giant Meccano on the Champ-de-Mars, in a record time of 22 months.