Ordensburg Vogelsang is a former National Socialist estate placed at the former military training area in Eifel National Park. The landmarked and completely preserved estate was used by the National Socialists between 1936 and 1939 as an educational centre for future leaders. Since 1 January 2006 the area has been open to visitors. It is one of the largest architectural relics of National Socialism. The gross area of the landmarked buildings is 50,000 m2.
The three buildings at Eifel have been known as 'NS-Ordensburg' since 1935. The first phase of the project was the construction of the Castle of Vogelsang, which with up to 1,500 workers took only two years. Several much bigger buildings were also planned, such as a huge library to be called the 'House of Knowledge' measuring 100 metres by 300 metres, a 'Kraft durch Freude' hotel with 2000 beds, and the biggest sports facilities in Europe. Construction at the site halted on the outbreak of war.
References:The Walls of Constantinople are a series of defensive stone walls that have surrounded and protected the city of Constantinople (today Istanbul) since its founding as the new capital of the Roman Empire by Constantine the Great. With numerous additions and modifications during their history, they were the last great fortification system of antiquity, and one of the most complex and elaborate systems ever built. They were also the largest and strongest fortification in both the ancient and medieval world.
Initially built by Constantine the Great, the walls surrounded the new city on all sides, protecting it against attack from both sea and land. As the city grew, the famous double line of the Theodosian Walls was built in the 5th century. Although the other sections of the walls were less elaborate, they were, when well-manned, almost impregnable for any medieval besieger.