Madrid has spent decades living alongside hills that did not arise from a whim of nature, but rather from the earthworks of major construction projects and urban transformations. Cerro del Tío Pío Park in Vallecas, popularly known as the “Park of the Seven Breasts,” is the classic example: seven artificial mounds built in the 1980s on top of a former shantytown and compacted rubble.
Today, history is repeating itself—but with a twist—in the southwest: the three mountains of Aluche, enormous mounds of earth created by the underground relocation of the A-5, are beginning to be leveled and transformed into a new, more pleasant, and less controversial landscape.
The Three Mountains of Aluche: Tunnel-Excavated Earth Transformed into Landscape
The work to bury the A-5 along Paseo de Extremadura has generated an enormous volume of soil excavated during the tunneling process. This material has been accumulating on the site of the former Iberdrola power substation, forming three large mountains of sand and soil that rise next to the Aluche neighborhood.
According to municipal data, some 170,000 cubic meters of earth have accumulated on that plot, raising the hills to a maximum height of about 18 meters. The visual and environmental impact has been immediate: a wall of earth facing the homes, the loss of open views, and a substantial alteration of living conditions and the environmental value of the area, as reported by residents and neighborhood associations.
Neighborhood opposition forced the project to be refined. The City Council announced that these piles of sand would not simply be a camouflaged landfill, but rather the seed of a new park integrated into the future Paseo Verde del Suroeste: three artificial hills with specific uses (a skate park, a lookout point, and picnic areas), connected to one another and to the area’s major green spaces, Casa de Campo and the Cuña Verde de Latina.
From mountains of rubble to a park with flattened hills
The latest development has unfolded in recent days. The City Council has begun removing part of the accumulated earth to lower the hills created during the excavation. The Aluche Mountains will go from their initial height of 18 meters to about 6 meters, a more reasonable scale for a neighborhood park and much less intrusive for nearby homes.
The excavated soil won’t go far: it will be reused to cover three former A-5 crossings and interchanges (Batán, Los Yébenes, and the Boadilla del Monte road), as part of the highway undergrounding project and the Southwest Greenway. In other words, the construction project itself is consuming its own mountains, transforming part of the highway’s elevation changes into connected green spaces.
The three underpasses will begin to be covered with soil in July, transforming into landscaped, walkable spaces that will connect neighborhoods previously separated by traffic. Thus, the very material that created a controversial landscape will serve to cap off an effort to stitch the city back together and reduce the impact of the A-5.
What the new park will be: a skate park, a lookout point, and a hub for biodiversity
Once leveled, the hills will not disappear; they will remain as gentle undulations in a park covering some 20,000 square meters—equivalent to nearly twice the size of the Plaza Mayor—integrated into the Paseo Verde del Suroeste. The project envisages three distinct sections:
- The northern hill will be dedicated to recreational use, featuring bleachers, a pump track, and a skate park.
- The western hill will serve as a lookout point and interpretive site for the green network of parks, offering views of Casa de Campo, the Cuña Verde, and the Paseo Verde del Suroeste itself.
- The southern hill will be dedicated to biodiversity and more tranquil uses, with a picnic area and a space for plant diversity, including the transplantation of some of the trees removed from the A-5.
The complex will be completed with energy-producing solar pergolas, pedestrian and bike paths, and recreational areas, integrating the new park into the large green infrastructure planned along the highway’s former route.
