The project of the architect Vittorio Meano, who at that time was building the Palace of the Argentine National Congress in Buenos Aires, was approved.

It was designed by Italian architects Vittorio Meano and Gaetano Moretti,[2] who planned the building's interior that is covered with marble.

[7] It connects the portico with the Hall of the Lost Steps, and it exhibits works of art such as "La Jura de la Constitución 1830" by Pedro Blanes Viale, and the "Encuentro de un Centauro Indio con el León Hispano" and "El primer surco", both by Manuel Rosé.

[8] In the nave of the building is the Hall of the Lost Steps (Spanish: Salón de los Pasos Perdidos), which is inspired by the cathedrals of the Renaissance and is composed of two vaults and a central skylight, which separates the two chambers in which the Senate and the House of Representatives meet.

[10][11] It has been the site of the lying in state of former presidents and ministers and lying in honor of several Uruguayan personalities, such as Juana de Ibarbourou (who also received the title of "Juana of America" there in 1929),[12] Mario Benedetti,[13] China Zorrilla,[14] Carlos Páez Vilaró,[15] Eduardo Galeano,[16] Carlos Maggi[17] and Alcides Ghiggia.