The late 19th and early 20th centuries marked a period of dramatic transformation in communication, transportation, society, and the arts. The opening of Carnegie Hall, visits from composers like Tchaikovsky and Dvořák, and the emergence of jazz and ragtime signaled a new musical era. These developments, along with the birth of broadcasting, recording, and film, set the stage for an explosion of creativity. The 1920s and 1930s were decades of contrasting affluence and hardship while musically, they witnessed the rise of a distinctly American sound. Composers and performers such as Aaron Copland, George Gershwin, Irving Berlin, Duke Ellington, and Louis Armstrong helped shape a cultural identity through music. By the 1940s, swing had the nation dancing, and Hollywood had embraced the power of the film soundtrack. New styles continued to evolve, laying the groundwork for modern popular music. Some of the most popular and influential music in all fields was created during these years, with many pieces remaining influential and beloved well into the 21st century.