The history of Antwerp’s underground canals

Beneath the bustling activity of the metropolis of Antwerp lies a hidden world—a forgotten network of canals, waterways, and moats known as “De Ruien.” What is an underground system today used to be open waterways during the Middle Ages.

A portion of this subterranean network has been opened to the public and can be explored via guided tours. We couldn’t miss out on this opportunity and descended into the depths!

The “Ruienstad”

Around the year 1250, Antwerp was already a “Ruienstad” (canal city). There was an extensive network of natural and man-made watercourses: the Ruien, Vlieten (streams), and Vesten (fortress moats). This system served two functions. First, it was used for defense, forming a system of moats around the city walls. Second, it created inland port facilities that linked the city center directly to the vital Scheldt River.

During Antwerp’s Golden Age in the 16th century – when the city rose to become Europe’s wealthiest trading metropolis – the open canals were the city’s lifeblood. They were used to transport goods directly from the Scheldt into warehouses and city markets. This transport of goods fueled the trade in cloth, spices, and other commodities that established Antwerp’s legendary wealth. The former presence of numerous bridges spanning the canal network is still visible today in street names like “Sint-Katelijnevest” or those containing the Dutch word “brugge” (bridge).

A Problem Begins

The city fathers recognized the problems associated with the open water system early on. The water became increasingly polluted and did not drain properly. They developed a flushing system based on sluices (schuiven). These sluices were closed at high tide to dam the water in the system and opened at low tide. The resulting strong current was intended to flush waste and debris from the canals into the Scheldt.

However, this solution was doomed to fail due to the city’s own success. Antwerp’s explosive growth into a metropolis led to a massive increase in population density and industrial activity. Tanneries, breweries, and countless households discharged their waste directly into the canals. The volume of pollution quickly exceeded the capacity of the tide-based flushing system. The canals turned into stinking, open sewers inhabited by all sorts of unwelcome residents.

The Great Vaulting

The unbearable smell hanging over the city and the constant threat of epidemics became the driving forces behind a centuries-long project: the complete vaulting (covering) of the canals.

The vaulting of the Ruien was a slow, gradual process that spanned more than 250 years. It began in the 16th century when the city administration granted private individuals permission to vault and build over the canal sections on their property at their own expense. To speed up this process and motivate citizens, the city even introduced financial bonuses for vaulting in the 17th century.

This approach created a unique architectural heritage underground. Since each owner was responsible for their own section, the materials and architectural styles used for the vaults varied significantly. The result is an underground mosaic of over 200 different vault types.

By 1835, 75% of the network was covered. It was finally completed in 1882 with the vaulting of the last open canal, the Brouwersvliet. With this act, the Ruien disappeared from the cityscape and were largely forgotten for over a century.

An Underground World – The Hidden Life of the Ruien

However, the canals were never entirely forgotten. During World War I, they were reportedly used to smuggle English goods into the German-occupied city. In World War II, the tunnels served as shelters and even as venues for celebrations during bombing raids. There are also unconfirmed reports that they were used by the Jewish population to escape, even though German occupation forces actively sealed and guarded the entrances.

The Rediscovery

After nearly a century of being “forgotten,” they were “rediscovered” in the 1960s. An increasing appreciation for industrial and infrastructural heritage sparked public interest in the Ruien.

Initial attempts to offer tours failed due to the unbearable stench. The city began preparing the canals for reopening, making modern adaptations that preserved the historical shell while fundamentally changing their function. The main issue was their role as an active sewage system. The solution was to install modern, closed sewer pipes within the historic tunnels.

In 2005, parts of the system were officially opened to the public, transforming the hidden canals into a tourist attraction.

Descending into the Tunnels

Entrance to the underground tunnels is only possible with a guided tour. We had booked our tickets in advance – which sell out quickly – and waited at the entrance for the tour to begin.

Important! The start and end points of the tour are different. You cannot take large items with you. Right at the start, we were each given a small backpack for our shoes, rubber boots, a helmet, and a thin pair of overalls. So, it was time to change! Afterwards, we were handed a tablet that provided historical information at specific points in multiple languages.

Then we descended a staircase and stood in the former sewer. The historic tunnels themselves no longer carry raw sewage. We waded through rainwater runoff from the streets and domestic “greywater” from showers and dishwashers. This water is much less hazardous to health and produces a more tolerable damp smell instead of a repulsive stench. The tour is about 1.5 kilometers long and leads over uneven, often muddy and slippery ground. Everything is shrouded in semi-darkness, broken only by strategically placed lighting and our flashlights.

The darkness and the environmental conditions have created a unique ecosystem. It is home to a significant rat population, and one or two animals crossed our path. Rare species of black and brown spiders also live here, which were pointed out to us. A particularly curious biological feature is a delicate white fungus that grows exclusively on rat droppings. All in all, it’s a world you shouldn’t feel fear or disgust toward if you want to dive into Antwerp’s underground.

The tour lasts about 90 minutes and is accompanied by a guide in addition to the tablet. Our guide did a great job leading us around the deeper patches of water and pointing out the creatures in the dark.

We have taken several underground city tours before; each has something special, and Antwerp was no different. Walking through old sewer trenches that are still in use today is quite an experience. We loved it!

Visitor Information

Address

Ruihuis, Suikerrui 21,
2000 Antwerpen

Website