Fortress of Ulm was one of the largest fortifications in Europe in the 19th century. After the withdrawal of Napoleon's army of the German Confederation was decided to build several fortresses in the country in order to strengthen the security of the German lands.

Ulm fortress was constructed from 1838 to 1859 to the north of the city under the guidance of architect Moritz Karl Ernst von Prittvitsa .  It's pretty typical for those times the construction of a polygon with a total length of the fortress walls of more than 9 km .  Inside, there are high-rise buildings of the barracks, designed to accommodate 5000 soldiers in peacetime and to 20 million in military .  Weapons installed as the defenders on the walls and on the roofs of the barracks .  The fortress wall had six gates and two railway tunnels .  At some distance from the fort on the south side of Ulm it was equipped with several well-fortified forts .  They were designed to protect the city from a direct attack .  Strategically the most important object - the only bridge over the Danube - was inside the fortress .  There were plans for further expansion of the Ulm fortress, but they were never implemented .  Yes, and by appointment Ulm fortress never used . 

During the Second World War fortifications were partially destroyed and continues to destroy the remains for several decades afterwards. Recently, the company of enthusiastic researchers Ulm fortress it was partially restored.