What phrase is used to describe the first era of american popular music in the 20th century?

The phrase Popular Music called Pop music became so popular during twentieth century in America. Gone were the days when music was confined only to music halls and opera houses. Advancement in music led various music artists to gain influence. The emergence of Jazz and Broadway music was well appreciated and gained a lot of prominence in twentieth century.

Pop music expresses the folk music and the black culture and started to gain significance from the mid nineteenth century. It included Broadway tunes and Ballads.

the recent bombing of the uss cole is one of many incidents of terrorism directed against the united states. more than 40 percent of the world’s terrorism is directed against u.s. targets.   pursue the alleged perpetrators through the criminal justice system, and still others would beef up intelligence capabilities. to deal with potential attacks involving weapons of mass destruction, some analysts advocate extending the reach of law enforcement agencies or spending more on domestic preparedness programs; others would encourage a policy of u.s. military restraint overseas to attempt to reduce the motivation for terrorist attacks on u.s. targets.

the tallest building in the western hemisphere and the sixth tallest building in the world