Construction of the Royal Palace of Naples was ordered and begun in 1600 by the Spanish Viceroy Fernando Ruiz de Castro for a visit (that, in the end, was never made) by the new King of Spain, Philip III Habsburg, to the Viceroyalty of Naples.
The project was given to one of the most famous architects of that time, Domenico Fontana, who had already built the majestic works commissioned by Pope Sistus V in Rome, but the work continued for decades and in many cases the original design by Fontana was modified. However, for the whole of the sixteenth century, the palace and the vast “Palace Square” where the main entrance is located (today “Piazza del Plebiscito”) were the beating heart of social and political life in Naples.
, Later the palace was known for its modern services and systems built according to the efficiency criteria typical of the dawning industrialization: gas lighting, advanced fresh-water distribution systems, steam machines for hydraulic services, new drainage and sewer systems, zinc plates instead of roof tiles, advanced foundry products to be used in the construction of the Belvedere Bridge and lighting systems, waterproof plastic products for critical joints, glasses and mirrors with a protective coating etc. were introduced.
The palace is well-known for its amazing tapestries, for the luxurious halls, for its Royal Court Theatre (where the opening session of the Conference will take place.) See Wikipedia page and for the nearby national library and San Carlo theater (see the Tourist Info section of the website).
More information at this link.