19世纪的黑尔戈兰岛属于丹麦王国。但 丹麦在基尔条约中将它割让给了 联合王国。它很快成了汉诺威上层阶级、艺术家和作家的旅游胜地。德国统一后英国在黑尔戈兰-桑给巴尔条约中将黑尔戈兰岛还给了德国。
The decision will appear after Germany is formed. One needs to invent "National Fraternity" in order to enact it. Once enacted, the Heligoland Island will have a German core. There's no consequences except maybe a worse relation with Britain.
Ingame description
The small North Sea island of Heligoland had become a British possession during the Napoleonic Wars, ceded formally by Denmark in the 1814 Treaty of Kiel. After the Unification of Germany the island became an object of desire for The German Empire, as the few inhabitants of the Island were by and large Germans.