You say “Liguria” and you think about sea and pesto, right? To prepare it according to the traditional recipe we use two protected-origin-denomination products: “Genoese basil” and Riviera Ligure extra virgin olive oil.
Perhaps for this reason it is so good. It is called pesto (literally “I crush”) because the ingredients are crushed in a marble mortar. It is the brightness of the Riviera, the characteristics of the soil and the brackish air that determine the qualities of protected-origin-denomination basil. 
The areas of production of protected-origin-denomination basil are Voltri, Prà, Coronata for Genoa, Diano Marina, Andora, Albenga for the Western Riviera and Val di Magra for the Eastern Riviera.