In 1909 Berg was appointed senior building official in Breslau (now Wrocław, Poland), in Silesia. His most notable contribution to architecture is the Jahrhunderthalle (Centennial Hall) built between 1911 and 1913 as part of a series of works commemorating the 100th anniversary of the 1813 War of Liberation against Napoleon Bonaparte. The Hall, an important early landmark of European reinforced concrete buildings, survived World War II, and in 2006 was designated a UNESCO World Heritage Site.