Short answers, pulled from the story.
Bill Haley's Rock Around the Clock became the first rock and roll record to top the Billboard magazine's main sales and airplay charts in 1954. This release opened the door worldwide for this new wave of popular culture.
Rock and roll originated in the United States during the late 1940s and early 1950s. The genre spread to much of the rest of the world shortly after its inception.
Cleveland, Ohio, disc jockey Alan Freed began playing rhythm and blues music for a multi-racial audience in 1951 and is credited with first using the phrase rock and roll to describe the music. Four years later, Bill Haley's Rock Around the Clock became the first rock and roll song to top Billboard magazine's main sales and airplay charts.
The Beatles' first appearance on The Ed Sullivan Show on the 9th of February 1964 drew an estimated 73 million viewers, at the time a record for an American television program. This event is considered a milestone in American pop culture and marked a major point in the British Invasion.
The Beatles' 1967 album Sgt. Pepper's Lonely Hearts Club Band is later regarded as a starting point for the album era. During this era, rock music transitioned from the singles format to albums and achieved cultural legitimacy in the mainstream.
The term heavy metal began to be used to describe some hard rock played with even more volume and intensity in 1967. The term was first used in music in Steppenwolf's Born to Be Wild in 1967 and became associated with bands like San Francisco's Blue Cheer, Cleveland's James Gang and Michigan's Grand Funk Railroad.