The fire destroyed a large part of the historic center of the city, including the cathedral, and caused a great change in the urban structure of Santander.

The triggering element of the catastrophe was the strong southeasterly wind that, since the afternoon of 15 February, hit the city, accompanied by an atmospheric depression of great intensity.

That same day, 24 hours after the fire started, firefighters arrived from Bilbao, San Sebastián, Palencia, Burgos, Oviedo, Gijón, Avilés and Madrid.

On the 20th the civil governor issued a decree obliging all owners to repair the roofs of buildings and smoke vents within 48 hours.

[6] In general, the fire affected the narrow streets (except for Atarazanas), with buildings basically constructed of wood and with bay windows that facilitated the spread of the flames.

Most of the medieval town was destroyed, the total were 37 of the oldest streets of the city that occupied 14 hectares, which meant the disappearance of 400 buildings, including homes (approximately 2000) and stores.

At the time of the disaster, the post of Special Government Delegate for the Reconstruction of Santander was created, which was in charge of the new area and the urban future of the city.

[7] The fire caused only one victim, Julián Sánchez García, a firefighter from Madrid who died in Valdecilla hospital after a slight recovery.

First of all, an attempt was made to solve the road problem by building a new route for the tramway that would overcome the dysfunctionalities resulting from the narrow and irregularly distributed streets of the historic center.

To this end, a project was accepted that followed the guidelines of the Ensanche model, with an orthogonal grid composed of wide streets in the areas of greatest traffic confluence.

The second fundamental criterion was given by the commercial orientation and wealthy residence that was given priority to this area, especially to the streets of San Francisco, Calvo Sotelo and Juan de Herrera.

Likewise, the need to build a main square as the new representative center of the city was upheld: the Plaza Porticada, home to some official buildings, such as the Civil Government, the Treasury Delegation, the Military Government, the Chamber of Commerce, Industry and Navigation, and currently also includes the headquarters of Caja Cantabria.

For this reason, time was devoted to the reconstruction of the cathedral of Santander, the church of the Annunciation and the construction of the Plaza de la Asunción.

Parallel to all of the above, two fundamental phenomena occurred: the displacement of the lower class population settled in the old houses of the center to the periphery, which led to the consequent growth of the city on its outskirts.

Thus, the area directly affected by the fire was remodeled through private initiative, which constructed buildings for official, commercial and bourgeois residential use.

On the other hand, it triggered a non-spontaneous mobilization of population of large proportions that ultimately leaves its traces in the current socio-urban structuring.