ɪt wʌz bˈɪlt ɐlˈɔŋ ɐn ˈeɪntʃənt tɹˈeɪdɪŋ ɹˈoʊd, kɹˈɔsɪŋ ðɪ ˈælps baɪ wˈʌn ʌvðɪ ˈiːziɪst pˈæsɪdʒᵻz, ðə kˈɑːl də mˈɔntdʒənˌɛvɚ.
It was built along an ancient trading road, crossing the Alps by one of the easiest passages, the Col de Montgenèvre.