The rich history of the 20th century directly inspired the diverse range of musical styles developed between 1900 and 1999. This era of music did not have a dominant style or sound, and composers created highly diverse kinds of music.
Perhaps the most salient common thread during this time period of classical music was the wider use of dissonance in composing music. Because of this, the 20th century is sometimes called the "Dissonant Period" of classical music.
The 20th century was also an age where recording and broadcast changed the economics and social relationships inherent in music. In the 19th century you had to possess talent to be able to enjoy music at home, or simply attend performances of others. But in the industrialized world every person suddenly gained access to radio, television and digital music, which expanded one's experience with most existing genres.