The tunnels were constructed from the nineteenth century onwards, when the clay pits close to the Rupel became exhausted and the extraction shifted further north, beyond roads and railway lines.

The workers started excavating tunnels to avoid having to climb the slopes of a road or railway line every time.

Tunnels under the tracks

Part of these tunnels, parallel to the railway line between Dendermonde and Antwerp, can be found in the Walenhoek nature reserve, a 60-hectare nature reserve where the clay pits of the former De Neef-Landuydt brickworks in Niel were once located .

The ponds in the forest have steep edges, which, according to the Nature & Forests Agency, indicate that they have been excavated with clay dredgers. Some wells are up to 30 meters deep. That is why swimming is dangerous due to the cold undertow in the water.

Narrow gauge

Oblivion

The last brickmakers' tunnel was closed in 1988. The dozens of tunnels ended up in oblivion. They were filled with earth or became overgrown with weeds and shrubs. Since 2017, the Steenbakkerstunnels working group has been examining the inventory of the old connecting roads. Some tunnels have since been restored or opened to cyclists and hikers.