Lake Avernus, near Naples, lies in the volcanic region of the Phlegraean ('Burning') Fields. In classical mythology these were the site of the Underworld, or 'Hades'. The entrance to Hades was said to lie in a nearby grotto, inhabited by a prophetess known as the Cumaean Sibyl.
In Virgil's epic poem, The Aeneid, the Sibyl helps Aeneas, the Trojan prince, to enter Hades. There his father's ghost foretells his destiny as the founder of the Roman nation. Such associations made Lake Avernus a major attraction for landscape artists and travellers on the Grand Tour.