The Macellum of Pozzuoli was the macellum or market building of the Roman colony of Puteoli, now known as Pozzuoli. When first excavated in the 18th century, the discovery of a statue of Serapis led to the building being misidentified as the city's serapeum or Temple of Serapis.
https://en.wikipedia.org/wiki/Macellum_of_Pozzuoli