Jazz began in the early 20th century as a kind of music of black Americans.

Jazz began in the early 20th century as a kind of music of black Americans. It was intended for singing, for dancing, mid for entertainment and atmosphere at parties or social gatherings.
    Jazz has continued to develop and has produced some of the United States leading singers, instrumentalists, and composers. Today, it’s considered by many to be America’s art music. It has also influenced almost every other kind of music in America, Europe, and even the Orient.
    Jazz represents a blending of musical elements from Africa and from Europe. Jazz uses some European ideas of harmony and melody, but the rhythms are more African in origin. And jazz is polyrhythmic, which means it uses many rhythms around one basic rhythm.
    The most important feature of Jazz is improvisation, to improvise means to make something up on the spur of the moment. This is the way jazz is usually played. Jazz musicians have learned to improvise so well that they can make up excellent melodies as they play. A good Jazz player seldom plays anything the same way twice.
    Thus, listening to jazz is not like hearing a piece of music that was written long ago. It is like being there when the music is first being made.