Alas Building, Rationalist skyscraper in San Nicolas, Buenos Aires, Argentina.

The Alas Building is a 141-metre, 41-floor residential and office tower in San Nicolás. A narrow rectangular tower with vertical ribs and rows of small recessed windows rises from a wider lower block; thin antennas stand near its flat top, and a band of glass runs along street level.

The building was created in 1950 as headquarters for a labor union federation and remained Buenos Aires' tallest structure until 1995, when other buildings surpassed it.In its early years it housed underground television studios that were later expanded as production facilities for Argentine public television.

The name ALAS means "wings" in Spanish; the Air Force coined it after taking over the unfinished ATLAS building (Agrupación de Trabajadores Latinoamericanos Sindicalizados) following the 1955 coup. The central block holds nine apartments per floor, and the building once had its own supply store and internal commercial premises for residents.

The building can be viewed from outside and offers a good starting point for exploring the neighborhood's architecture.Since it is an office building, interior access is limited, but the exterior facade clearly displays its rationalist design features.

Perón ordered an underground bunker built into the plans in case of war or a coup, but he did not use it during the 16 June 1955 bombing of Plaza de Mayo by the Argentine Navy. After the 1955 coup the bunker became studios for Argentine public television, which moved to Figueroa Alcorta Avenue in 1978.