I haven’t been here (yet).
Centennial Hall in Wrocław
The Centennial Hall, a landmark in the history of reinforced concrete architecture, was erected in 1911-1913 by the architect Max Berg as a multi-purpose recreational building, situated in the Exhibition Grounds. In form it is a symmetrical quatrefoil with a vast circular central space that can seat some 6,000 persons. The 23m-high dome is topped with a lantern in steel and glass. The Centennial Hall is a pioneering work of modern engineering and architecture, which exhibits an important interchange of influences in the early 20th century, becoming a key reference in the later development of reinforced concrete structures. [source]