The American Civil War was fought from 1861 until 1865, between the Union (North) and the Confederacy (South). The primary reason for the outbreak of conflict was that the South no longer felt that it had any say in the running of the national government; they felt marginalized and that their economic interests (particularly the institution of slavery) were under threat. The war ended with a Union victory and the maintenance of the United States of America as one whole country. 

Jim Crow Laws were designed to enforce racial segregation of whites and blacks in the Reconstruction-era South. They were also designed to try and prevent blacks from voting or from achieving social mobility. Most of the Jim Crow Laws were in effect for much of the second half of the nineteenth century and the first half of the twentieth century.

The Reconstruction period of American history occurred in the decades after the Civil War. It is named after the attempts by the United States government not only to reconstruct the internal infrastructure and industry of the nation, but also to "reconstruct" the feeling of unity and solidarity between the North and the South. It is a period of time marked by existing intense sectionalism and racial segregation.

The Wade-Davis Bill was proposed by radical Republicans in 1864, when it was becoming clear that the Confederacy was going to lose the Civil War. The Wade-Davis Bill represented an attempt to make it more difficult, and more humiliating, for the states of former Confederate politicians to reintegrate themselves into the Union. The Bill was opposed by Abraham Lincoln, who favored a ten-percent plan, which required only ten-percent of those who had voted in 1860 to swear allegiance to the Union government. Lincoln felt that the Wade-Davis Bill would hinder the development of positive relationships between the North and South and so employed his veto.

Given that Andrew Johnson was the first President to be impeached (his trial famously failed to convict in the Senate by one vote) and that radical Republicans controlled the House after the Civil War, it is obvious that their relationship would have been negative. The radical Republicans wanted harsh terms imposed on the former Confederate states, whereas Johnson favored reintegrating smoothly and easily. The disagreement between the two groups led to the impeachment of Andrew Johnson in 1867.

The Wade-Davis Bill was proposed by two radical republicans in 1864 in an attempt to make readmittance into the Union very challenging and humiliating for former Confederates. Under the plan, the Union army would take control of enforcing the end of slavery, and any Confederate politician who wanted to reenter Union political life would have to swear both complete loyalty and that he or she had never been personally culpable for encouraging rebellion during the Civil War.

During the second half of the nineteenth century, the United States engaged in a massive railroad construction project. This linked communities over vast distances for the first time in American history. The First Transcontinental Railroad was built between 1863 and 1869 and finished in 1869, with the initial first destination being San Francisco.

The Emancipation Proclamation was issued in 1863, in the middle of the Civil War, by President Abraham Lincoln. The Proclamation formally stated that the slaves living in the territories currently in open rebellion were now and forever free.

The Balfour Declaration was published in 1917 and proposed to create a new nation for the Jewish people in the territory of Palestine. This nation would come to be called Israel. It represents a massive milestone in the Zionist movement to achieve an independent Jewish nation.

The Atlantic Charter was an agreement signed between the United States and Great Britain in 1941. It proposed the ideal manner in which the war and the post-war world should be conducted and shaped. It was later supported by the other allied powers and led to the creation of the United Nations.