Between 6 December 1916 and November 1918, the city was occupied by German forces as a result of the Battle of Bucharest, with the official capital temporarily moved to Iași (also called Jassy), in the Moldavia region. After World War I, Bucharest became the capital of Greater Romania. In the interwar years, Bucharest's urban development continued, with the city gaining an average of 30,000 new residents each year. Also, some of the city's main landmarks were built in this period, including Arcul de Triumf and Palatul Telefoanelor. However, the Great Depression in Romania took its toll on Bucharest's citizens, culminating in the Grivița Strike of 1933.