Chateau de Laeken (Royal Castle of Laeken), Brussels

Nestled within the expansive Royal Domain of Laeken, a park inaccessible to the general public, stands the stately Royal Castle, which, in fact, functions as a palace and serves as the primary residence of the Belgian royal family. This palace was constructed in 1790 and counts Napoleon Bonaparte as one of its most famous historical occupants. The French emperor stayed here on multiple occasions and even signed the declaration of war against Russia within its walls in 1812.

Just beyond the palace lies the Serres Royales, a collection of enormous greenhouses originally commissioned by King Léopold II. Spanning nearly four acres, these vast structures provide shelter for an astonishing array of tropical and Mediterranean plant life. While truly remarkable, the greenhouses are only accessible to the public for a brief period of ten days each year, typically from late April to early May. During this time, the queues to visit these botanical wonders can be quite lengthy, making advance planning advisable.