Castel dell'Ovo is a seafront castle in Naples, located on the former island of Megaride, now a peninsula, on the Gulf of Naples in Italy. The castle's name comes from a legend about the Roman poet Virgil, who had a reputation in the Middle Ages as a great sorcerer and predictor of the future. In the legend, Virgil put a magical egg into the foundations to support the fortifications. It remains there along with his bones, and had this egg been broken, the castle would have been destroyed and a series of disastrous events for Naples would have followed. The castle is located between the districts of San Ferdinando and Chiaia, facing Mergellina across the sea.

Naples is the regional capital of Campania and the third-largest city of Italy, after Rome and Milan, with a population of 909,048 within the city's administrative limits as of 2022. Its province-level municipality is the third-most populous metropolitan city in Italy with a population of 3,115,320 residents, and its metropolitan area stretches beyond the boundaries of the city wall for approximately 30 kilometres.