Commemorative plaque to Carlos María de Castro, Madrid

The commemorative plaque to Carlos María de Castro sits on the facade of a small palace-style building at Calle Fernando el Santo 14, in the Almagro neighborhood of Madrid's Chamberí district. It honors the man whose plans permanently reshaped the layout of the Spanish capital.

Who was Carlos María de Castro?

Carlos María de Castro (1810–1893) was a Spanish engineer and architect, best known as the author of the 1860 "Plan Castro" — the blueprint for Madrid's Ensanche, the 19th-century expansion of the city beyond its old historic walls. His plan laid out the rectangular street grid and defined the boundaries of new districts that still exist today, including Salamanca, Chamberí, and Arganzuela. It remains one of the most influential urban planning documents in the city's history, and the grid pattern it introduced still governs how central Madrid, outside the old town, is organized.

What does the plaque commemorate?

The plaque was installed in 1991 on the initiative of the Ayuntamiento de Madrid (Madrid City Council), on the facade of the small palace that Castro designed and built for himself, and where he lived until his death. Its inscription records that this was the residence of the engineer, architect, and designer of Madrid's expansion. Known as the Palacete de Carlos María de Castro, the building is a good example of the elegant townhouse architecture built in Madrid during the second half of the 19th century — the very period in which his own expansion plan was being carried out across the city.

How do you get there?

The plaque sits in a quiet corner of Almagro, a short walk north of Paseo de Recoletos and Plaza de Colón. The easiest way in is by metro to Rubén Darío or Alonso Martínez (lines 5 and 10), both roughly a 10-minute walk from Calle Fernando el Santo. Several bus routes running along Paseo de la Castellana, Madrid's main north–south avenue, also serve the area.

What else is worth seeing nearby?

Almagro is one of Madrid's more refined neighborhoods, lined with eclectic townhouses from the late 19th and early 20th centuries. A walk through the surrounding streets turns up further examples of the residential architecture built during the Ensanche era — a tangible result of the very plan associated with the man the plaque commemorates. It pairs naturally with a stroll toward Paseo de Recoletos or Plaza de Colón.

When should you visit?

This is a low-key, historically minded spot rather than a crowded tourist attraction, so it can be visited comfortably at any time of year. Spring and autumn are the most pleasant seasons for walking the neighborhood, since Madrid's midsummer heat can make longer strolls less enjoyable.

Frequently asked questions

Where exactly is the plaque located? On the facade of a small palace at Calle Fernando el Santo 14, in the Almagro neighborhood (Chamberí district).

Who was Carlos María de Castro? A Spanish engineer and architect, author of the 1860 urban expansion plan for Madrid known as the Plan Castro, or Ensanche.

When was the plaque installed, and by whom? In 1991, on the initiative of the Ayuntamiento de Madrid (Madrid City Council).

Can you go inside the building? No — the palacete is a private building, so visits are limited to viewing the facade and plaque from the street, which is accessible year-round without restriction.