[2][3] Built in the late 20th century after a 1977 political reform, the complex is located in Mexico City about a mile east of the Zócalo central square, in the Venustiano Carranza borough, next to the Palace of Federal Justice.

Thereupon, construction on a new seat of the Legislative began as a part of a plan of urban restructuring of the sector where the San Lázaro Station was located, on the limit of the Venustiano Carranza and Cuauhtémoc boroughs.

The project, which was promoted by former president José López Portillo, was a faction of a massive development and public works program of the government, resulting from a Mexican petroleum boom.

Construction began in September 1979, following the plans of architects Pedro Ramírez Vázquez (who at the time served as Secretary of Settlement and Public Works), Jorge Campuzano, and David Suárez.

[14] During the hearing, what were alleged to be two extraterrestrial corpses from Peru were unveiled, with Maussan claiming support from Mexican authorities and the National Autonomous University of Mexico (UNAM).

[19] The main facade of the building, which is located on Congreso de la Unión Avenue, is made up of three sections: the two ends are lined with red tezontle and the central one with white marble, forming a wide access plaza between them.

The central motif of the sculptural ensemble is the national coat of arms, surrounded by a series of moving flags symbolizing the plurality of thoughts; faces emerge from the banners that represent the popular movements that Mexico will see.