The gardens date of the 18th century, but King Leopold II changed the its garden-architecture. A brand new complex was commissioned by King Leopold II and designed by Alphonse Balat. Built between 1874 and 1895, the complex was finished with the completion of the so-called “Iron Church”, a domed greenhouse that would originally serve as the royal chapel. The total floor surface of this immense complex is 2.5 hectares (270,000 square feet).