Although the Dutch film industry is relatively small, there have been several active periods in which Dutch filmmaking thrived. The first boom came during the First World War when the Netherlands was one of the neutral states. Studios like Hollandia produced an impressive cycle of feature films. A second wave followed in the 1930s, as talking pictures led to a call for Dutch-spoken films, which resulted in a boom in production: between 1934 and 1940, 37 feature films were released. To accommodate the rapid growth, the Dutch film industry looked to foreign personnel experienced with sound film technology. Mostly these were Germans who had fled their country as Hitler took power. Several renowned German directors who would go on to work in Hollywood directed films in the Netherlands in this period, most notably Douglas Sirk (Boefje, 1939).