The second time I entered the underground world of Naples was to visit the Bourbon Tunnel – or Galleria Borbonica. This is an underground labyrinth with long corridors and stone chambers typical just like bunkers, where you will find old Italian cars and scooters, alongside some Second World War relics.

The Galleria’s official documents declare: “The Bourbon Gallery and the surrounding underground environments represent a description of the last 500 years of Naples’ history. “We work to give glory to those who lived underground and realized magnificent works, and we give back memories of those who suffered terrible experiences but survived thanks to this underground world.”

It has a long and complex history, but there is nothing better than taking a guided tour to discover that, among other things, this space has served as a shelter for the city’s residents in time of war.

The renovation of this station was part of The Art Stations project to bring more light and beauty to some of Naples’ metro stations. The work at Toledo was designed by the Spanish architect Oscar Tusquets Blanca, with “water and light” as the main theme. It is a huge contrast with the traditional Spanish Quarter on the surface, which I think is one of the best places to stay in Naples – and one of the most interesting to explore on foot.

While it is true that it is just a staircase, the visual effect is so spectacular that it is really worth your while heading over to the Toledo Metro station. It is just one more of the unmissable underground attractions in Naples.

Visiting the Catacombs of San Gennaro was without doubt one of the most remarkable experiences of my time in Naples. It is an underground cemetery, carved into the porous rock on the side of Capodimonte to the north of the city. It is composed of by a number of interlinked underground chambers on various levels that have been created over time.

A local community initiative was responsible for restoring the catacombs, with the work to restore, preserve and open them to tourists as a way to improve the Rione Sanità neighbourhood, create employment, and fund the restoration work.

Whether or not you believe in the miracle associated with the blood of San Gennaro, a visit to the catacombs is one of the things that absolutely must be on your list of things to do in Naples. This is because, in addition to the unique architecture, the catacombs are also home to a significant collection of 9th and 10th-century frescoes and mosaics. Absolutely not to be missed!