Which Italian regions make up the industrial triangle of Milan, Turin, and Genoa?

The industrial triangle of Italy, which connects the cities of Milan, Turin, and Genoa, is formed by the following three administrative regions:

• Lombardy: Home to Milan, which serves as the region's capital and a primary industrial and commercial hub.1
• Piedmont: Home to Turin, the region's capital and a major center for automobile manufacturing and other diversified industries.2
• Liguria: Home to Genoa, the regional capital and a vital port city that hosts significant shipbuilding and iron industries.3

Together, these regions constitute the "first Italy," a historical and economic designation that distinguishes this core industrial area from the "third Italy" of small-to-medium enterprises and the "second Italy" of the Mezzogiorno.4