The Puerta de Alcalá is one of the five ancient royal gates that gave access to the city of Madrid. It is located in a strategic place, as it is in the centre of the roundabout in the Plaza de la Independencia. At the crossroads of the streets of Alcalá, Alfonso XII, Serrano and Salustiano Olózaga, next to the gates of the Retiro: Puerta de España, Puerta de la Independencia and Puerta de Hernani.

The gate gave access to travellers entering the town from France or Aragon in the past. Today it is a monumental gate located next to the Cibeles Fountain and the Retiro Park. It was built by order of Charles III to replace an earlier gate that had existed since the 16th century and was designed and built by the Italian architect Francesco Sabatini. Other projects by Spanish architects competed with Sabatini: Ventura Rodríguez and José de Hermosilla, with Sabatini's design finally being chosen personally by the King.

It is a neoclassical gate with a monumental appearance similar to the Roman Triumphal Arch, and was erected facing east on the outside in 1778.

Since its beginnings, it has undergone several urban transformations in its surroundings, going from being the external border of Madrid to a tourist centre of obligatory passage that appears to be inserted almost in the middle of the city itself. This change was due to the 19th century expansion along the Serrano neighbourhood and the extension of Calle de Alcalá. It was declared a historic-artistic monument in 1976, extending its status to the Plaza de la Independencia itself.

Since the end of the 18th century, the gate has been acquiring relevance in the people of Madrid, and by the end of the 19th century it was already one of its most characteristic icons, appearing in numerous illustrations of the city. As it is one of the most representative monuments, in its dual condition of looking inwards and outwards from the city, the Puerta de Alcalá has served as a symbol of the city. The Puerta de Alcalá has served as a support for all kinds of political and artistic manifestations and numerous historical events have taken place in its vicinity.

Over time, the gate and its appearance have acquired the status of a symbol of Madrid. It appears in postcard albums, in logos and ideograms representing "what is Madrilenian". Some works of the genre "chico" have been inspired by the gate.

In 1986 a song was released in Spain under the name ¨La puerta de Alcalᨠcomposed by Bernardo Fuster and Luis Mendo, members of the Madrid group Suburbano, and Miguel Ángel Campos and Francisco Villar, popularised by Ana Belén and Víctor Manuel and centred on the homonymous monument in the city of Madrid.