Géopolitique, Réseau, Énergie, Environnement, Nature
Charleroi, from fortified city to sought after city
Issue #4


Issue #4


Bas Smets

Published by the Groupe d'études géopolitiques, with the support of the Fondation de l'École normale supérieure

Charleroi, city of ambitious projects 

The city of Charleroi, in Belgium, has a very distinctive history. Since its creation, the city has grown through a series of ambitious projects. Designed by Vauban in 1666 as a fortress, it is perched on a rocky spur. Its defenses were expanded in successive stages.

Two hundred years later, after the discovery of coal deposits in the region, Charleroi became coal mining’s epicenter. In 1911, a new district was built to host the World’s Fair, the height of the city’s Belle Époque.

And so, the city of Charleroi never saw organic or linear development. It was developed to meet the needs of specific functions: first, defense; then, mining. Consequently, Charleroi was never designed as a ‘livable’ city. Its inhabitants were a by-product of other purposes.

Since the industrial crisis, the city has lost its second purpose. Three hundred and fifty years after its creation, Charleroi is in search of a history that can inspire a new future.

The urban revitalization of the upper city follows in the tradition of ambitious projects. This project offers the rare opportunity to imagine a new history, inspired by the intrinsic qualities of this extraordinary city. What was once a fortified and isolated city, an industrialized and exploited city, we can now envision as a welcoming and attractive city, one that is sought after and sustainable. It is a city which is deeply rooted in its region and connected to its surrounding landscape.

From ‘Black Country’ to a metropolitan landscape 

Charleroi benefits from an exceptional location. A rocky spur, naturally protected by the Sambre Valley and two of its tributaries, was chosen as a stronghold. The citadel became the upper city, and the surrounding countryside was changed over time.

To the north of the city, a chain of slag heaps rose — a by-product of coal mining. These slag heaps created microclimates that are different from the region’s natural cli

mate and so have become a refuge for animal and plant species that are rare in Belgium. They form a unique topographic landscape, providing the city with a distinctive backdrop.

During the era of coal mining, these heaps were served by a railway which has become a soft mobility path which links the different heaps. Built on top of the former track’s ballast, the path resembles a dry riverbed.

To the citadel’s south lies the Sambre Valley and the canal that was dug into one of its tributaries. Together, these waterways carve out a wet valley, along which a number of industries developed, and which are now undergoing redevelopment.

These three major features — the rocky spur, the chain of slag heaps, and the wet valley — are bordered by the fields of Brabant to the north and by the Ardennes’ wooded foothills to the south.

In his landmark book about Los Angeles, Reyner Banham defines that complex city through various ‘ecologies’: spatial systems with their own geomorphology, internal logic, use, and identity. Through this new reading of the urban environment, Banham disrupted and expanded the traditional view of cities.

For Charleroi, these landscape features can be considered ‘Banham-ian ecologies’. A close study of existing physical elements allows the most relevant and enduring to be distilled. This mapping reveals and reinforces Charleroi’s three ecologies: the rocky spur, the chain of slag heaps, and the wet Sambre valley. Together, these three ecologies form a metropolitan landscape, a large-scale frame of reference that anchors all elements in the region: the slag heaps, the highways, the metro, the citadel, the Sambre, and its industrial heritage.

The ‘Black Country’ is evolving into a metropolitan landscape, and Charleroi is becoming the Los Angeles of Belgium!

Plateau & glacis

Successive expansions of the fortification paralleled a gradual transformation of the natural landscape. The rocky spur’s plateau was converted to a fortified citadel, while the surrounding slopes were transformed into exposed glacis. The plateau and glacis subsequently developed separately following their own course.

On the plateau, the citadel’s streets were built in long, straight lines to ensure the best defense. The streets were not laid out to ensure optimal visibility. All the streets lead to a central square, built around a spring. Designed in a hexagonal shape, this square is the fortress’ heart.

The terrain around the citadel was developed into a glacis. This military term refers to “an area of open land, generally built into a gentle slope, situated around a fortified site, in order to provide a clear field of vision.” Following the removal of the fortifications, the glacis’ flat surface allowed major public amenities to be built. This is where the football stadium, the hospital, the BPS22 art museum, the library, the police station, the courthouse, and the Palais des Beaux-Arts — among others — are found. These facilities often include large parking areas.

Superimposing a map of the last Dutch and Belgian fortifications over the modern urban fabric reveals the transformation of military elements into urban forms. Within these fortifications, the orthogonal street system is found. On the exterior are found the public facilities, parking areas, and fragmented parks. Wide boulevards have been laid out along the former fortifications. The highway that circles the city follows the old tributaries on either side of the rock on either side of the rock.

The dual plateau-glacis system was based on natural topography. This urban development project allows for a return to regional roots by inverting the military approach.

The redevelopment of the plateau’s streets and squares offers the opportunity to redefine the identity of these public spaces. The fortified city is therefore transformed into a desirable city with a network of squares and the introduction of greenery in the streets.

The glacis, once open, is transformed into a park system encircling the plateau, integrating the city’s public amenities into a coherent spatial pattern.


We can identify three urban features on the plateau: boulevards, streets, and squares. After the fortifications were taken down, large boulevards were built where the ramparts once stood. With their rows of tall trees, these boulevards provide visual continuity. This forms a ‘tree loop’ around the city center, serving as a landmark in the urban fabric.

The streets have been invaded by cars. The project reduced the width of the roads in order to widen sidewalks. Trees were planted in the streets, in rectangles cut into the paved space.

These trees provide the visual presence of greenery while taking up minimal public space. They are positioned in a way to help organize parking. Like natural ‘pixels’, these planted rectangles are a reminder of the pioneering trees that were the first to grow on the slag heaps.

The third feature is made up of public spaces. Place Charles II, Place Manège, and Square du Monument provide breathing room in the dense urban fabric of the upper city. These public squares gave cars too much space. The project rethinks these spaces as a connected network.


A study of the site highlights three elements located in the footprint of the former glacis: public facilities, parking areas, and small parks. The public facilities form a ring around the city center, complementing the city’s dense urban fabric. The large parking areas can be landscaped in order to expand the bits of existing parks. This would allow these three elements to form a ‘wooded glacis’ and a true ‘parks system’, as described by landscape architects such as Frederick Olmstead and Nicolas Forestier.

A network of public squares

The upper city’s different squares offer the possibility of creating a true network of public spaces. A specific identity is proposed for each square in order to create a whole, each with its own ambiance and characteristic. The Place Charles II will regain its place as the city center’s epicenter, Place du Manège becomes the market square, and Square du Monument becomes a small square and playground for the surrounding neighborhood.

The squares are connected by redeveloping the surrounding streets. The rue Dauphin will link Place Charles II and Place du Manège, while rue de la Régence will link it to the Square du Monument. This network of public squares is complemented by the new bus station, built over the metro’s roof.

This network of public spaces provides breathing room in a dense city while showcasing public buildings such as the City Hall, the Basilica, and the Palais des Beaux-Arts. The squares help structure events in Charleroi, its weekly market, special concerts, and improve the quality of daily life.

Place Charles II

Place Charles II is made into a central, pedestrian square. The concentric hexagonal shape is transformed into a webbed pattern whose points connect with the surrounding streets.

The project uses the hexagonal shape as an essential element for the square. A graphic design on the ground made up of interlocking hexagons transforms the fortress’ hexagonal footprint into a dynamic shape. The lines, laid out in natural stone, will contrast with the square’s blue paving stones. These lines are used to install water fountains. In nice weather, the square can transform into a giant water fountain, providing an oasis to residents and visitors.

In the center, where the fortress’ water well was once located, a reflecting pool is installed, designating the city’s epicenter. This reflecting pool reflects the sky, creating a feeling of intimacy and infinity.

A central water fountain can be turned on for special occasions. This jet can concentrate the power of all the jets around it to surge several meters above the square!

Place du Manège

The open-air parking area was converted to a public space reserved for pedestrians, located between the Palais des Beaux-Arts and the City Hall’s bell tower.

A grid of tall trees was planted at large intervals, creating a space that is open and understated. This large distance maintains the visual continuity between Place Charles II and the Palais des Beaux-Arts and allows many uses, such as markets or carnivals. Installations requiring more space can be set up in Place Charles II and the metro roof’s terrace.

The trees cast a grid on the ground, struck through by stripes of blue paving stones. The tree chosen for the square is the Gingko Biloba. At once graceful and eye-catching, this tree takes up little space while introducing a real natural element. Following the seasons, its colors change from an electric green in the spring to an intense yellow in autumn. And so, Place du Manège gains its own identity while allowing for a variety of uses.

Square du Monument

The Square du Monument was an island surrounded by streets. The project removed the street on one side of the square as well as the connection between the two streets. The square was therefore enlarged and renovated from one end to the other. This square is intended to become a meeting place for locals. The leveled surface allows for different types of games, such as pétanque.

The outdoor furnishings were designed with Mullen Van Severen designers as objects that invite exploration. The renovation of Square du Monument gives it an entirely new identity, inviting new uses.

Green roadways

There are two types of roads on the plateau: boulevards and streets. The boulevards follow the footprint of the former fortifications and are nearly twice as wide as the streets found within the fortress.


The boulevards were planted with large trees and form a ring around the city center. We are proposing to expand this ‘tree loop’ which creates a link between the city center and the surrounding public facilities. This loop is intended to become an urban feature that increases the visibility of the urban fabric, helping to orient residents and visitors.

The redevelopment of Boulevard Jacques Bertrand follows this logic. The tree loop was expanded, the roadway reduced, and large sidewalks were created along the building fronts.


The streets had been taken over by cars. The project enlarged the sidewalks and, when possible, a rectangle was cut out of the pavement in order to install a tree layer. Our proposal is to plant the same pioneer species that colonized the slag heaps to introduce pixels of nature into a dense and paved city.

These rectangles space out parking spots and help combat heat islands. Wider sidewalks and greenery are helping to transform the fortified city into a welcoming and pleasant city.

Wooded glacis

A new model for the university campus

For the World’s Fair, prestigious buildings were constructed at the outer limits of the last fortification. Today, they are being reimagined as a campus in the American tradition, a true gathering place for students. The adjoining public space is made up of a raised esplanade, located above the tunnel. The tunnel’s conversion allowed the public space above to be reimagined. Reducing the size of the road allowed a large lawn, punctuated by trees to be installed around the tunnel.

A series of small squares are found at building entrances. Today, the tree loop is interrupted due to the tunnel. New landscaping on either side completes the loop that crosses the campus. As a result, the campus is connected to the city through this tree loop, while at the same time forming part of the wooded Glacis system.

The boulevard Gustave Roullier tunnel was turned into underground parking thanks to a detailed cross-section study. The redevelopment of the northern entrance ramp reduced the roadway’s footprint. The project made it possible to demolish the structure protruding into the natural terrain in front of the Université du Travail, keeping the paving stone level throughout.

The project replaces the exit ramp with a large staircase that leads to Place du Manège and the Palais de Beaux-Arts. The parking area is connected to the city by two distinctive entrances: one on the square in front of the Alfred Langlois Library, and the other on boulevard Solvay. These openings create natural ventilation and allow plenty of light to enter the parking garage. Natural light makes the stairs and elevators to the campus visible.

Landscape & climate 

Based on an analysis of the existing landscape, we are proposing three main features for revitalizing Charleroi’s upper city: the network of public squares, the planted road network and the wooded glacis. Together, these features create an independent and sustainable landscape. Planting trees will aid in evapotranspiration.

Similarly, planting pits are designed to store rainwater. Specific types of vegetation are selected for each feature. The choice takes into account two major factors: the site’s conditions (sunshine, wind, existing vegetation, etc.), and the roles that vegetation can play in this specific location (contributing to the fight against urban heat islands, creating ambience and landscape identity).


After winning the competition in 2014, it has taken almost 10 years to complete construction. The project is in keeping with the dynamic spirit that has characterized Charleroi since its inception: that of transforming what already exists.

The Place du Manège parking area has been transformed into a verdant square, the Square du Monument has become a neighborhood playground, the university campus has been turned into a park, the narrow streets are dotted with trees, the tunnel and underground passageway have been converted into an underground parking lot, the metro roof has been converted into a bus station, and the Place Charles II has been restored to its role as the city’s epicenter.

Three hundred and fifty years after the citadel was built, the city of Charleroi is entering a new phase, that of a desirable and attractive city.

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Bas Smets, Charleroi, from fortified city to sought after city, Jan 2024,

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