Heraclium is on the Bay of Naples and was buried by 30m of ash during the eruption of Vesuvius that destroyed Pompeii in 79CE.

They are talking about Herculaneum (https://en.wikipedia.org/wiki/Herculaneum), which when I visited it showed signs of being a serious hoax perpetuated to garner tourist money. They were visibly constructing a city out of whole cloth, under the guise of "restoring the ruins." Very different from Pompeii.