The Obelisco de Buenos Aires (Obelisk of Buenos Aires) is a national historic monument and icon of Buenos Aires. Located in the Plaza de la República, in the intersection of avenues Corrientes and 9 de Julio, it was built to commemorate the fourth centenary of the first foundation of the city.
Construction began on March 20, 1936, and it was inaugurated on May 23 of the same year. It was designed by architect Alberto Prebisch (one of the main architects of the Argentine modernism who also designed the Teatro Gran Rex, in Corrientes and Suipacha) at the request of the mayor Mariano de Vedia y Mitre (appointed by president Agustín Pedro Justo). For its construction, which cost 200,000 pesos moneda nacional, 680 m³ of concrete and 1360 m² of Olaen white stone from Córdoba were used. Its height is 67.5 m, and 63 m of these are up to the initiation of the apex, which is 3.5 m by 3.5 m. The tip is blunt, measuring 40 cm and ends in a lightning rod that can not be seen because of the height, whose cables run through the interior of the obelisk.
[excerpted from Wikipedia]