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 ancient Argos Theater was built in 320 BC. and is located in Argos, Greece against Larissa Hill. Nearby from this site is Agora, Roman Odeon, and the Baths of Argos. The theater is one of the largest architectural developments in Greece and was renovated in ca 120 AD.
The Hellenistic theater at Argos is cut into the hillside of the Larisa, with 90 steps up a steep incline, forming a narrow rectilinear cavea. Among the largest theaters in Greece, it held about 20,000 spectators and is divided by two landings into three horizontal sections. Staircases further divide the cavea into four cunei, corresponding to the tribes of Argos A high wall was erected to prevent unauthorized access into the theatron and may have helped the acoustics, but it is said the sound quality is still very good today.
Around 120 CE, both theaters were renovated in the Roman style.