With an estimated value of between 300 and 500 million euros, that of Villa Certosa is among the most expensive properties ever to appear for sale on the Italian market. Located in Porto Rotondo, a hamlet of Olbia near Punta Lada, used by Silvio Berlusconi as a summer residence, spread over 4,500 square meters, with a park of 126 hectares, it has hosted in its 126 rooms some of the most important heads of state and government: George W. Bush, Tony Blair, Mirek Topolánek, Vladimir Putin, José Zapatero and José María Aznar. It was acquired by Berlusconi in the late 1980s and renovated by architect Gianni Gamondi, known for designing numerous exclusive villas and luxury residences, particularly on the Costa Smeralda. Having been appraised by the Cavalier in 2021 (then estimated at €259 million), and after his death put up for sale by his sons in 2024 for €500 million, it had received the attention of the Sultan of Brunei, among others. The negotiations, in which Dils, the Italian real estate services company also indirectly owned by Barbara, Luigi and Eleonora Berlusconi, was then the exclusive agent, are now being led by Sotheby's International Realty, with the collaboration of Knight Castle Real Estate and another American company.