The next bridge featured in the Dezeen A-Zdvent calendar is almost invisible, sunken down below the surface of a moat outside a historic Dutch fort.
Designed by architecture studio RO&AD, the bridge goes by many names, including Trench Bridge, Sunken Bridge and Moses Bridge. It is located at Fort de Roovere, the largest fort built in the 17th century on the West Brabant Water Line.
The design is intended to preserve the legacy of the moat – building a bridge over the water, especially on the side the enemy was expected to arrive on, would have been improper.
Instead, RO&AD concealed the pathway below the water, like a trench. From afar, it is completely hidden, allowing visitors to cross the moat unnoticed.
"The bridge can't be seen from a distance because the ground and the water come all the way up to its edge," explained the architects.
"When you get closer, the fortress opens up to you through a narrow trench. You can then walk up to its gates like Moses on the water," they added.
The walls of the trench are wooden sheets, protected from water damage and fungal decay with a layer of rubber foil. Hardwood provides the ground surface, which includes staircases leading down into the passage at either end.
Since completing the Trench Bridge in 2011, the team has also built a snaking bridge over another fort moat in the city of Bergen op Zoom.
In the spirit of an advent calendar, Dezeen is counting down the days until Christmas with an A to Z of iconic contemporary bridges. See all the bridges in our A-Zdvent calendar so far »