The original gardens of the Royal Palace of Laeken date back to the 18th century, but King Leopold II drastically changed their appearance.

[2] The first construction phase took place between 1874 and 1893, ending with the completion of the so-called Iron Church, a domed greenhouse, which would originally serve as the royal chapel.

The octagonal Palm Pavilion was furnished as a bedroom and connected to the palace by a subterranean corridor where Leopold received his mistresses.

[5] After the king's death in 1909, the greenhouses were preserved, but the Iron Church was converted into a private royal bathing house.

Every year in the spring, the greenhouses are partially opened to the public for twenty days at the request of Leopold II.

[2] The greenhouses are also sometimes used today for contemporary art exhibits and displays, such as Alexandre Dang's The Dancing Solar Forget-Me-Not for the International Day of Missing Children (in cooperation with Child Focus) in 2010.

This formed a first step towards Art Nouveau architecture that was further developed by Victor Horta who served as an apprentice of Balat.

The existing neoclassical Orangery from 1817–1819 by the architects Guislain-Joseph Henry and François Verly is connected to the Palace via the Theatre Greenhouse.

The start and end points of the trusses rest on the ground so that the greenhouse presents the image of a glass dome supported by flying buttresses.

Finally, in 1893, the Iron Church was added, a neo-Byzantine ensemble surrounded by wreath chapels, the dome of which is supported by twenty columns of Scottish granite.

It is the opportunity to discover one of the most remarkable monuments of Belgian heritage and to admire the collections of exotic plants and flowers, some of which have been brought back from expeditions to the Congo for Leopold II.