Fort Douaumont was the largest and highest fort on the ring of 19 large defensive forts protecting the city of Verdun, France since the 1890s. It has a total surface area of 30,000 square metres and is approximately 400 metres long, with two subterranean levels protected by a steel reinforced concrete roof 12 metres thick resting on a sand cushion. These improvements had been completed by 1903. The entrance to the fort was at the rear. Two main tunnels ran east-west, one above the other, with barracks rooms and corridors to outlying parts of the fort branched off of the main tunnels. The fort was equipped with numerous armed posts, a 155 mm rotating/retractable gun turret, a 75 mm gun rotating/retractable gun turret, four other 75 mm guns in flanking 'Bourges Casemates' that swept the intervals and several machine-gun turrets.
By 1915 the French General Staff had concluded that even the best-protected forts of Verdun could not resist bombardments from the German 420 mm Gamma guns. These newly deployed giant howitzers had easily taken several large Belgian forts out of action in August 1914. As a result, Fort Douaumont and other Verdun forts were judged ineffective and had been partly disarmed and left virtually undefended since 1915.
On 25 February 1916, Fort Douaumont was entered and occupied without a fight, by a small German raiding party comprising only 19 officers and 79 men. The easy fall of Fort Douaumont, only three days after the beginning of the Battle of Verdun, shocked the French Army. It set the stage for the rest of a battle which lasted nine months, at enormous human costs. Douaumont was finally recaptured by three infantry divisions of the French Second Army, during the First Offensive Battle of Verdun on 24 October 1916. This event brought closure to the Battle of Verdun in 1916.
Today Fort Douaumont is open to the public.
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.