'We are in extreme crisis.' Italian parmesan producers fear for future amid drought

The main artery that cuts through Italy's heartland, where 30% of its food is produced, is the 650-kilometer-long (400-mile-long) River Po, which winds its way from the Alps to the Adriatic Sea on Italy's northeast coast.

The "Big River," as it is known, plays an integral role in the nation's history. Before bridges were built, its deep waters protected civilizations on either side from invaders who could not cross.

In later years, cities and industries sprouted on its banks and made use of the water for hydropower, transportation and irrigation. Along some sections of the River Po, processing plants turn the muddy river into drinking water.