Obelisco de Buenos Aires

The large obelisk at the intersection of Avenida Corrientes & Avenida 9 de Julio is in many ways the symbol of Buenos Aires.

It was designed by architect Alberto Prebisch and constructed in quicktime between March 20 and May 23 1936. It was built to commemorate the 400th anniversary of the foundation of Buenos Aires using concrete and Olaen white stone from Córdoba.

Reference:
Wikipedia: Obelisk of Buenos Aires