Which of the following DOCGs is not situated on the slopes of ancient volcanoes?

Barbaresco DOCG is indeed the correct choice as it is not located on the slopes of ancient volcanoes. Instead, Barbaresco is situated in the Piedmont region of northwestern Italy, where it benefits from the region’s unique geography and climate, primarily characterized by the rolling hills of the Langhe. The area is renowned for its red wines made from the Nebbiolo grape, thriving in the limestone and clay soils rather than volcanic soils.

In contrast, the other DOCGs listed in the question are associated with volcanic activity. Soave DOCG, located in the Veneto region, is on the foothills near the ancient volcano of Mount Berici. Colli Euganei DOCG features wines produced in a hilly area that is underpinned by volcanic soil, originating from the Euganean Hills, which are remnants of an ancient volcanic landscape. Lacryma Christi DOCG, located around Mount Vesuvius, is renowned for its wines produced in the rich volcanic soils that confer distinctive minerality and flavor characteristics.

Understanding the geographical context of each DOCG is crucial, as it influences the grape varieties grown, the styles of wine produced, and their overall quality.