Surroundings

In 1964, Antonio Lamela presented a project entitled "Planning of Plaza de Colón," advocating for open, high-rise buildings. In the journal Arquitectura, he reflected on the lack of an efficient and up-to-date General Urban Development Plan, which forced private developers to anticipate the plans—an undesirable situation that fostered land speculation and increased construction costs.^[12] He submitted two "volume planning projects" to the City Council for the plots located on either side of the intersection of Calle de Génova and Plaza de Colón, proposing high-rise, freestanding buildings. His idea was based on maximizing the use of ground-floor space by reducing the visual impact of the structure and facades that did not reach the ground, in what he called "suspended architecture," referring not only to its structure but also to the pedestrian's perception from ground level.^[13] In his project, he aimed to create a cohesive urban unit, balanced between the corner masses, expand pedestrian space both in sidewalks and in the permeability of the site by allowing pedestrian traffic on the ground floors of the buildings, obtain a good view from Jorge Juan and Goya streets, and solve the problem of lack of parking.^[14]

Urban planning

Within this urban planning context, the architectural project for the Columbus Towers was conceived, and construction began in 1968. In 1969, the Old Mint was demolished, and a public competition for ideas—unusual at the time—was launched to design the site as a landscaped public space.^[15] The competition requirements included the creation of a commemorative framework for the historical event of the Discovery of America and its representative figures, an underground public parking garage with a capacity for 1,000 vehicles, a landscaped area, and a solution to the traffic problems at the intersection.^[16] Lamela's project eliminated the section of Jorge Juan Street adjacent to the National Library building, removing the fences and iron railings, as he considered the concept of walled enclosures typical of early 20th-century buildings outdated; this created a superblock for public facilities.^[16] It also involved the creation of an overpass over Recoletos-Castellana, facilitated by the topography of Génova and Goya streets, which descend to Plaza de Colón.^[16] For the western part of the plaza, Lamela reused the volume arrangement project already submitted to the City Council in 1964.^[16] 580 technicians from different specialties entered the competition; Antonio Lamela received an Honorable Mention.^[16]

Initial design concept (1968)

Both towers had always been planned with a rectangular, not square, floor plan, with the Castellana tower facing parallel to the avenue and the Genoa tower facing south. The staircases were located at the rear, that is, to the north in the tower facing Genoa and to the west in the tower facing Castellana.^[17] The elevators were in the central core, in a group of three, one of them a double-cab elevator for use as a freight elevator.^[17]

The project was conceived for residential use from the outset. Numerous designs and layouts were considered, including three, two, and one apartment per floor, featuring large cantilevered terraces that were highly sought after at the time.^[17] Its use as tourist apartments managed by a hotel chain was even considered, an innovative concept that had proven successful in more tourist-oriented areas.^[17] Ultimately, the riskiest option was chosen: one apartment per floor with the finest possible finishes and luxuries.^[18] To facilitate marketing, a full-scale model was built in Las Pueblas, elevated one story above the ground, faithfully recreating the interior layout and materials used as a "show apartment." The residential use plan was short-lived, as the halt in construction prevented the proper marketing of the residential units. The show apartment was used for many years by a family close to the Osinalde family until it was demolished.^[18]

The towers have a suspended structure; the building consists of two pillars together on top of a platform from which hang two large towers with perimeter beams six feet singing with pendulums each floor with cable-stayed steel cables. Construction commenced with the concrete footings, the two central pillars and the upper platform. Then the towers were built from top to bottom, from the upper platform plant to plant closer to the base of the building. At the base, three floors (six floors including basements) were built from the bottom up.^[18]

First design (1976)

The building consists of a base or podium upon which rise two twin towers of orange-brown color, topped by two greenish crests joined by a plug-shaped finial from which the emergency staircases hang. The building has three elevators in each tower and two elevators on the parking levels.^[19]

The base is reminiscent of the nearby building at Génova 27, also designed by Estudio Lamela, before its renovation by the same firm between 2003 and 2005. The original 1974 project, during the height of the oil crisis, aimed for "natural climate control and self-protection," achieved through angled glass to minimize solar exposure. The two twenty-story towers rise from the podium, one projecting forward of the other rather than parallel. The typical floor plan of the tower is quadrangular, but not perfectly square. With a floor area of 607.74 m², it consists of a reinforced concrete central core containing four openings: three for elevators and a fourth for wiring and other installations. The façade features double- glazed glass: the first pane has a sawtooth pattern, while the second, installed during the 1990s renovation, is uniform with rounded corners. Each tower is topped by a greenish, quadrangular crest joined by a semicircular, plug-shaped structure.^[20]

Suspended structure

What makes this building stand out is its technical innovation, since for various reasons the floors had to be built in reverse, that is, "from top to bottom." Choosing a traditional structure would have made vehicle access to the basement levels impossible, as the necessary pillars would not have left enough space for ramps, and would have reduced the usable space for parking. This space was crucial due to the already small size of the plot (1700 m²).^[21] Furthermore, the new municipal ordinance required a minimum of 150 parking spaces.^[22] This approach resulted in completely open-plan floors, free of pillars and beams, allowing for maximum flexibility in the layout and better use of the usable area without obstructing the horizontal utilities.^[23] Furthermore, thanks to the transmission of loads through the core, one of the towers could be projected up to 9.5 meters above Genoa Street, as there were no supports obstructing pedestrian traffic.^[24] However, the choice of this method resulted in an increase in construction costs of between 10 and 15% compared to the traditional pillar structure.^[25]

This suspended or hanging structure model was novel because until then only seventeen towers in the world had been built using this system, such as the Commercial Union Building (now St. Helen's or Aviva Tower) or 20 Fenchurch Street (demolished) in London, the BP Building in Antwerp, the Standard Bank Centre in Johannesburg, or the BMW Headquarters, among others.^[26] Subsequently, Spanish architecture adopted the hanging model, developing in other cases the experience originating in the Columbus Towers.^[26]

The towers are designed in a way that departs from the traditional skyscraper or tower scheme, their main peculiarity being that the building's loads are transferred to a cap structure located at the top of the building and from there are conveyed, through a central concrete core, to the foundations. The loads are transmitted to the central core directly or through the cap structure, ultimately being transferred to the ground by means of a 13x13 m footing, 7 meters deep.^[27]

Through the suspended structure, the horizontal supports extend towards a structural system located at the top of each tower. This system consists of four beams, crisscrossed in pairs, with depths decreasing from 5 to 3 meters, forming a tic-tac-toe grid. These beams, also called radial beams, were constructed on formwork. The lower half was built first, then the upper half, and finally the 3-meter-deep perimeter tie beams, visually forming an irregular 3x3 grid.^[27] All of these were made of post-tensioned reinforced concrete. Sufficient space was left in the center of this inverted aerial foundation structure to house the machine rooms for the elevators and other building services.^[27]

From the perimeter beams hang a total of 18 post-tensioned concrete tie rods or pendulums, arranged at regular intervals on the façade, which allow for the attachment of the prefabricated anodized aluminum exterior cladding that, in turn, houses the air conditioning ducts. The 21 floor slabs of the towers rest on this system via their outer edges. These slabs are made of lightweight reinforced concrete and are supported on the central core by means of gusset plates embedded within it.^[27]

Structural issues

The building was originally intended for luxury apartments of 400 square meters. In August 1970, it was claimed that the Madrid City Council had ordered the "demolition of the excessive construction",^[29] and that the building had exceeded the permitted height by two floors and should be reduced by nine meters.^[30][31] In any case, the developer won the lawsuit, and the compensation that the council owed him was so high that it instead allowed him to change the use from residential to commercial, that is, to house offices, which was much more profitable at the time.^[32] Construction remained halted until 1973.^[33]

According to a news item in La Vanguardia from July 1974, the works would be completed the following spring (1975) and more than 100 million pesetas had been invested in the construction to date - the only data we have on the cost of the works. At the foot of the towers we find an urban sculpture called Heron, by José Luis Sánchez Fernández from 1975.^[34]

Opening

The towers were inaugurated in 1976. On November 15, 1977, the towers were advertised in the newspaper La Vanguardia as "high-end luxury in the heart of Madrid," whose commercial office space offered the following amenities: telex, internal telephone, piped music, carpeting, hot and cold air conditioning, and parking for 200 vehicles.^[35]

1990s

The first renovation, carried out between 1990 and 1993, significantly altered the building's original appearance, transforming it from two twin towers joined by a base into a single building. In the original 1967 design, Lamela failed to consider a suitable solution for building evacuation. His proposal was a fabric chute down which fire victims would slide directly to the street, like a slide. It didn't occur to anyone that this posed a significant risk to anyone using it, for example, from the twentieth floor. In 1989, Estudio Lamela was commissioned to find a solution. Due to new regulations, an emergency staircase was required, as the building lacked one. Since there was no space to install it, the solution was to run a beam between the two towers and suspend the staircase in the center, outdoors. This effectively made the towers appear as a single structure. Between the two roofs, a central finial was installed, which from then on was common to both towers. This finial, known as the controversial Art Deco "plug ," was designed to conceal the antennas and other machinery that had been added to the building.^[36] Two long-range spotlights were planned for the plug's prongs, but these were ultimately not installed due to their high cost.^[37] Neon light strips that changed color along the length of the enclosure were also installed, but these are now obsolete.^[37][38] Furthermore, taking advantage of the construction work, the towers were clad with a uniform bronze-tinted glass curtain wall to improve their thermal and acoustic insulation.^[36] The renovation cost 800 million pesetas. Following this renovation, the building's height increased from 86 meters above ground level to 110 meters due to the installation of the central finial. Several antennas are mounted above the finials of this finial, raising the maximum height to 116 meters. The result significantly altered the building's profile, making it taller and easily recognizable from a distance. Controversy about its aesthetic value still persists among Madrid residents.^[39]

2000s-2010s

In 2009, the building owner commissioned Schindler Spain to renovate its elevators, as the old ones had reached the end of their useful life. They were replaced with double-cabin elevators, capable of serving two floors simultaneously and with greater capacity, and equipped with the latest safety, energy efficiency, and technological systems.^[40]

During 2012, the interior of the towers was remodeled without evicting its tenants.^[41] The project, undertaken by Estudio Lamela, consisted of adding escalators to access the lobby (located below street level) and a large glass box that houses a panoramic elevator and an emergency staircase. The project had a budget of €300,000.^[42] After a year of work, the entrances, lobby, common areas, floors, and garages were renovated, as well as the entire electrical system of the building. Colón model doors, specially made for the office lobby, were also installed.^[42]

In January 2017, Mutua Madrileña announced its intention to undertake a comprehensive renovation, which could involve, among other things, joining the two towers and cladding them.^[43] In 2016, the Madrid City Council authorized the use of the towers for residential and hotel purposes.^[44] After the death of architect Antonio Lamela, his project was revealed, which restores the building's original design: increasing the space between floors, thus reducing the current number of floors from 20 to 13, and building another seven above the roof, removing the antennas from the power outlet and utilizing the current 116 meters.^[45] This is just one of several projects that the new owner has under consideration for its renovation, so it is not certain that it will be carried out.^[45]

Final renovations (2020–2024)

In December 2019, Mutua Madrileña presented a new renovation project, which began in 2020 and was completed in 2024. This renovation replaced the Art Deco plug-shaped finial with a four-story structure rising above the two towers. The project, designed by architect Luis Vidal, did not affect the building's total height of 116 meters, but increased its floor area by adding the new structure and integrating the two towers, which were previously joined only by a fire escape. The floors at the base were also removed. The renovation cost 65 million euros.^[4]

Carlos Lamela, son of the architect of the towers and president of the Association for the Protection of the Colón Towers, filed an administrative appeal against the Madrid City Council for allowing the original project to be distorted.^[46] The City Council had considered protecting the building two years before the proposal for its comprehensive renovation, without implementing any protection measures or doing so in a timely manner.^[47]

The renovation carried out by the insurance company Mutua Madrileña, inaugurated in 2024, modified all the landmarks of these towers considered iconic, such as the warmth of the glass of their facade, their Art Deco crown, and their characteristic silhouette against the Madrid skyline.^[48]

The influential architect Rem Koolhaas paid no attention to any contemporary buildings in central Madrid except for the original appearance of the Columbus Towers, which have been altered beyond recognition.^[49]