King Henry VIII. The leader of the Anglican Church, which was the Church of England, was the ruling Monarch.
The Niagara Movement was a civil-rights group founded in 1905 near Niagara Falls. Scholar and activist W. E. B. Du Bois gathered with supporters on the Canadian side of Niagara Falls to form an organization dedicated to social and political change for African Americans. Its list of demands included an end to segregation and discrimination in unions, the courts, and public accommodations, as well as equality of economic and educational opportunity. Although the Niagara Movement had little impact on legislative action, its ideals led to the formation of the National Association for the Advancement of Colored People (NAACP) in 1909.
Well an obvious answer would be slavery, depending on how late you're talking. After slavery ended, the country began what is known as the "industrial revolution". The north had already begun industrializing for a while, but in the 1870's and beyond, things ramped up quite a bit. Factories for clothes, shoes, farming equipment, packaged foods, and etc. became more popular. You also had coal mines, railroads, and steel mills. This showed the country was moving in the direction of mass production, and moving away from agricultural ways of living. This also meant child labor, which led to many child labor laws in the later years. This also meant many moved out of farming communities, and into larger, noisy, and crowded cities. Many immigrated to the US to take advantage of that, which led to some tension between communities.
Hope that helps!
This term is most commonly used to refer to the Soviet-American Cold War.