Postage stamps and postal history of Heligoland

During the period when Heligoland (a German island in the North Sea) was a British possession, about 20 postage stamps were issued between 1867 and 1890. There were up to eight printings of a single denomination and also a large volume of reprints which are known as the Berlin, Leipzig and Hamburg Reprints, respectively.

Source: Wikipedia — Postage stamps and postal history of Heligoland (CC BY-SA 4.0)