In the world there are many wonderful places with a great history behind it. It is the case of the famous German island of Wilhelmstein an artificially raised island in Lake Steinhude and noted for its beauty and for its unusual square shape.
Steinhuder Meer, is a German lake situated northwest of the city of Hannover and is where we find the hero today, the island that is called Wilhelmstein. This island in the middle of the lake is not natural, but that was commissioned more than 300 years ago by Duke William of Schaumburg-Lippe. As you you can imagine, raising an island of nowhere in the middle of a lake with the technology that existed at that time, it did not have to be anything simpler, when he decided to give it a square shape.
At first, the fort was composed of 16 small islands which were then joined together to reach the present form the complex. Its construction was intended to serve as a defense in case of attack Duke in his life and only had to use once.
Today, the island is used as a military academy, it also houses a museum. During good weather, in the port they dock small boats with people who want to visit this curious island. Large ships can not reach it due to its shallowness.
Source — Unusual Places, official website