Esperanto
Proposed microstates and micronations

Beginning in 1908, there were efforts to establish the world's first Esperanto state in Neutral Moresnet, which at the time was a Belgian – Prussian condominium in central-western Europe. Any such efforts came to an end with the beginning of World War I and the German invasion of Belgium, voiding the treaty which established joint sovereignty over the territory. The Treaty of Versailles subsequently awarded the disputed territory to Belgium, effective January 10, 1920.

The self-proclaimed micronation of Rose Island, on an artificial island near Italy in the Adriatic Sea, used Esperanto as its official language in 1968. Another micronation, the extant Republic of Molossia, near Dayton, Nevada, uses Esperanto as an official language alongside English.
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