Up to about 1915, movies were short and programs were made up of several works. Then Griffith and other began to make longer films which provided the same powerful emotional appeal as did melodrama and presented spectacles for beyond what the theater could offer. Consequently, after World War-I, increasing number of spectators deserted the theater for the movies. This trend was accelerated in the late 1920's as a result of two new elements. In 1927, sound was added to the previously silent film, and then one of the theater's principal claims to superiority vanished. In 1929, a serious economic depression began. Since audiences could go to the movies for a fraction of what it cost to see a play, theater-going became a luxury which few could afford. By the end of World War-II, the American Theater had been reduced to about thirty theaters in New York city.