Visiting Pozzuoli (near Naples)

Pozzuoli is fantastic. It is accessible by the train from Naples. The port has ferries to Ischia and Procida as well as a fabulous fish market. The Roman amphitheater is right in the center of town and close to the train station. Close by you can visit Cuma and the Cave of the Sibyl, and Lago Averno, which was the inspiration for the entrance to the underworld by Virgil in the Aeneid. If you are adventurous, you can go see the Sulfatara, but I’m not sure how close you can get to it anymore. The area is quite unstable and there have been many small earthquakes recently.

The importance of Pozzuoli turns up in unexpected place in history. Being the birthplace of Sophia Loren would be good enough for most places, but Pozzuoli was also the birthplace of the modern science of geology. In 1830, Charles Lyell showed that the columns of Macellum proved the existence of subsidence and uplift and his book began to explain earth's origins: https://washingtonlandscape.blogspot.com/2014/05/2014-geologic-pilgrimage-macellum-of.html
The area also provided the beginnings of concrete and thus modern construction. The volcanic soil of the area, when mixed with lime and water form a strong material called pozzolanic concrete which the Romans used for the gravity-defying roof of the Pantheon in Rome: https://www.sciencealert.com/we-finally-know-why-ancient-roman-concrete-stood-the-test-of-time