Jazz has its roots in a number of other musical forms: band music, spirituals, blues, and ragtime.
After years of warlord infighting, some of the major factions were exhausted, while striking workers agitated for reform. It was time for the United Front to make its move, but the untimely death of Sun Yat-sen complicated the picture.
Warren Harding was very much a hands-off kind of leader. This worked well when he appointed capable cabinet secretaries, especially Secretary of State Charles Evans Hughes.
Gandhi returned to India during the Great War, but needed some time to reacquaint himself with the country after being away for so long. The British promise more self-rule, but the ruthless killing of hundreds of peaceful, unarmed civilians in Amritsar is for many Indians the last straw.