Ferrara is inscribed in the World Heritage List of UNESCO since 1995, according to this criterion: "considering that the site is of outstanding universal value, being a Renaissance city, remarkably planned, which has retained its urban fabric virtually intact and for representing the concept of the "ideal city"… the completion of this project marked the birth of modern town planning and influenced its subsequent development". SInce 1999 UNESCO decided to adjoin the Este ducal residences in the Po Delta, so now the inscription is: "Ferrara, City of the Renaissance and its Po Delta" which illustrate the influence of Renaissance culture on the natural landscape in an exceptional manner. The Delta can be defined a "cultural landscape", an "open air museum" and a "technological landscape" for the presence of castles and rural residences named "delizie", as Belriguardo, Verginese, Mesola, rich from the artistic point of view, and for of the big work of drainage and canalizing until the sea, where the gulf of Goro was supposed to become a big port contrasting the trades of Venice. The Master of land reclamation, Alfonso II was the last of the Este family, so Ferrara and the Delta became part of the Vatican State and all the land works were abandoned.