In 1873, architect Alphonse Balat designed for King Leopold II a complex of greenhouses which complement the castle of Laeken, built in the classical style. The complex has the appearance of a glass city set in an undulating landscape.

The monumental pavilions, glass cupolas, wide arcades that cross the site like covered streets, are much more than an anecdote on the architectural applications of iron and glass or on little greenhouses of exotic plants. What the Royal Greenhouses express concerns architecture and, specifically, a major construction programme: the "Ideal Glass Palace".

The present-day plant collection at the Greenhouses in Laeken is valuable from three viewpoints :

• Some of the plants belonging to King Leopold II's original collections still exist.
• The current collections still respect the spirit that prevailed when the original collections were planted.
• Finally, the Royal Greenhouses still contain an enormous number of rare and valuable plants.

Each year, in the spring, the Greenhouses of Laeken are opened to the public, during almost three weeks. This tradition has been carried on for a century.