Music written since 1900 is called 20th century music. There have been more types and styles of music written in the 20th century than ever before. In the 20th century, the only limit is the imagination of the composer. This wide variety of musical styles reflects the diversity of life at the beginning of the 20th century. More people were free to choose where to live, how to earn a living, and how to spend their time. The car, the airplane, the telephone, the phonograph, the cinema, and the radio have all made the world more accessible and expanded the range of experiences. Technological developments have also had an influence on 20th century music, particularly electronic music. Like everyone else, musicians were affected by the political, economic and social problems of the 20th century. Hitler's rise to power in Germany in 1933 had a particularly dramatic impact on the lives and careers of musicians. Many composers left Europe for the United States. These refugees made enormous contributions to musical culture. One of the most significant changes in the components of music that has shaped 20th century music is rhythm. Modern music is full of complex rhythms and time signatures. The main reason for the increase in rhythms in 20th century music is the development of ballet. The second component of 20th century music is melody. This new music moves away from the traditional melodic line developed by previous musical styles. Modern composers have also rejected...