The Zonienwoud (also known as the Foret de Soignes & the Sonian Forest) is a remnant of the Roman Silva Carbonaria which once extended from the banks of the Rhine and the Moselle all the way to the North Sea. Over the centuries it has shrunk to its present form, which covers approximately 45 square kilometers on the southeastern edge of Brussels. From the twelfth century it became a hunting ground for the Dukes of Brabant and it has close historical links with a number of monastic orders (especially the Capuchin).
The forest consists of mainly European beeches and oaks, with seventy percent of the forest consisting of beech trees. This association with the beech largely dates from the times of the Austrian Habsburgs who commissioned the landscape architect Joachim Zinner to make beech plantations on a massive scale. His most memorable plantings are the beech cathedrals that survive today, with the best examples being found in the area know as the Kapucijnenbos.
In 2017 the Zonienwoud was awarded UNESCO World Heritage Site status when it was incorporated into the multinational "Primeval Beech Forests of the Carpathians and Other Regions of Europe".