I visited the " Palácio Itamaraty" of Brasilia on 2019 (October 1st).
The Itamaraty Palace was designed by Oscar Niemeyer, and open to the public on April 21, 1970 (construction started in 1960). Located in the Monumental Axis, east to the National Congress Building, it's the headquarters of the Brazilian Ministry of Foreign Affairs.
The building is also known as "Palácio dos Arcos" (Palace of the Arches), due to his peculiar facade that consist in a series of similar size semi-circular arches with very narrows lanes. The structure/material is exposed concrete, and was designed by the structural engineer Joaquim Cardozo (designer of most of Niemeyer's buildings).
As recurrent theme in all the palaces design by Nimeyer for the city, the architecture consists in in glass box contained between two concrete slabs supported by a colonnade in all facades.
The columns have a peculiar trapezoidal shape, that make them look thin from the outside.
The interior building (glass box) is structurally independent from the facade building.
Architect and traveler.