San Marzano Italian peeled plum tomatoes with basil are the most sought-after tomatoes in the world. These tomatos are grown in the San Marzano Valley at the foot of Mt. Vesuvio in Naples. The fertile volcanic soil gives the tomatoes a perfect balance of sugar and acidity. La Valle has been packing this exquisite tomatoes since 1949. San Marzano tomatos are ideal for sauces because of their great taste and low acidity.