which opened the Retiro Park (an amusement park) there in 1939; the rest was later mostly used as parking lots. Early plans The underutilized state of an area so close to the financial and administrative center of the city prompted the Municipal Department of Planning in 1956 to draft an urban renewal plan for the district. This envisaged the construction of a highway that would extend from Tigre to La Plata, as well as rezoning Catalinas to allow for the construction of office buildings of up to 70 floors. This district, per these plans, would ultimately be known as the "Catalinas Gateway" to Buenos Aires. The City Office of Regulatory Planning (OPRBA) further specified, in its revised master plan of 1958, that construction of skyscrapers in downtown Buenos Aires would be prohibited, and limited these to the Catalinas district. Mayor Hernán Giralt presented a project to the City Council for the development of "an area of hotels, an office and retail center, a location for shipping companies and air travel, a recreation center and a large area for parking," and on February 3, 1960, the Argentine National Congress authorized the City to purchase land north of Catalinas for the purpose. The Catalinas Norte Commission was established in 1961, but a subsequent political and economic crisis caused the project to stall and ultimately be discarded. The final draft The coup d'état that toppled President Arturo Illia in 1966 led to the dissolution of OPRBA. Mayor Eugenio Schettini instructed the Municipal Department of Architecture and Urbanism (MCBA) to design a new, simpler plan that would limit permits for office high rises. A municipal ordinance in 1967 parceled the land in accordance with the 1958 master plan, and lots were sold to Aerolíneas Argentinas, Conurban S.A, IBM, Sideco, Kokourek S.A, SEGBA (the state-owned city electric utility), Sheraton, and the Argentine Industrial Union (UIA). Retiro Park was bulldozed, and the Buenos Aires Japanese Gardens therein were relocated to their present, Palermo Woods location. The MCBA, in turn, retained four areas, opened three parking lots, and built two promenades: Carlos Della Paolera and Ingeniero Butty. Development Ground was broken on the first buildings in the complex, the Kokourek Group's Conurban Tower (in April 1969), and the Sheraton Buenos Aires Hotel & Convention Center, on June 26. Work began on the Carlos Pellegrini Tower for the UIA in 1970, and on the Catalinas Norte Tower (for