In the 1920s, Wittig's style became very popular in Poland and abroad, mostly due to its monumentalism, which was a leading trend in Polish architecture of the 1920s and 1930s. As a result of which he went on to create numerous monuments. Among the most notable is the monuments to Polish Military Organization in front of the Zachęta. It was destroyed by the Germans prior to the Warsaw Uprising, but reconstructed in 1999. Another notable work is the 1931 monument to World War I airmen. The Germans destroyed it by removing the sculpture from the top of its pedestal in 1940, but it was rebuilt in 1968 by Alfred Jesion. In 1932, Wittig also prepared the monument to Juliusz Słowacki, which was not erected until 2001, well after his death in Warsaw in 1941, during the Nazi occupation of Poland.