Following the Napoleonic Wars, the 1815 Congress of Vienna redrew the map of Europe. However, a major sticking point arose near Aachen over a tiny parcel of land spanning roughly 3. 5 square kilometers.
The area contained Vieille Montagne, one of the richest zinc mines on the continent. Neither the Kingdom of Prussia nor the United Kingdom of the Netherlands wanted to yield control of this vital economic asset to the other. In 1816, a compromise was struck: the town of Moresnet itself went to the Netherlands, Prussian Moresnet went to Prussia, and the mine along with the surrounding village became Neutral Moresnet.
Managed jointly by two royal commissioners, the territory effectively existed in legal limbo. It possessed no formal constitution, no standing military, and relied on the outdated Napoleonic legal code. Residents were considered stateless, exempt from military conscription in neighboring powers, and enjoyed exceptionally low taxes, turning the area into a haven for smuggling, distilling, and gambling.
Over the decades, attempts were made to formalize its identity, including an ambitious plan in the early 1900s to transform Neutral Moresnet into Amikejo, the world's first Esperanto-speaking microstate complete with its own anthem. This utopian vision was cut short by World War I when Imperial Germany occupied the territory. Finally, under the 1919 Treaty of Versailles, Neutral Moresnet was officially annexed by Belgium in 1920, bringing an end to Europe's most bizarre geopolitical anomaly born from raw mineral wealth.