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 GenoaDiano MarinaAndoraAlbenga for the Western Riviera and Val di Magra for the Eastern Riviera.