The American Civil War (1861–1865), often referred to as The Civil War in the United States, was a civil war fought over the secession of the Confederate States. In response to the election of an anti-slavery Republican as President, 11 southern slave states declared their secession from the United States and formed the Confederate States of America ("the Confederacy"); the other 25 states supported the federal government ("the Union"). After four years of warfare, mostly within the Southern states, the Confederacy surrendered and slavery was outlawed everywhere in the nation. Issues that led to war were partially resolved in the Reconstruction Era that followed, though others remained unresolved.

In the presidential election of 1860, the Republican Party, led by Abraham Lincoln, had campaigned against expanding slavery beyond the states in which it already existed. The Republicans strongly advocated nationalism, and in their 1860 platform they denounced threats of disunion as avowals of treason. After a Republican victory, but before the new administration took office on March 4, 1861, seven cotton states declared their secession and joined to form the Confederate States of America. Both the outgoing administration of President James Buchanan and the incoming administration rejected the legality of secession, considering it rebellion. The other eight slave states rejected calls for secession at this point. No country in the world recognized the Confederacy.

A civil war is a war between organized groups within the same nation state or republic, or, less commonly, between two countries created from a formerly united nation state. The aim of one side may be to take control of the country or a region, to achieve independence for a region, or to change government policies. The term is a calque of the Latin bellum civile which was used to refer to the various civil wars of the Roman Republic in the 1st century BC.

A civil war is a high-intensity conflict, often involving regular armed forces, that is sustained, organized and large-scale. Civil wars may result in large numbers of casualties and the consumption of significant resources.

Civil wars since the end of World War II have lasted on average just over four years, a dramatic rise from the one-and-a-half year average of the 1900-1944 period. While the rate of emergence of new civil wars has been relatively steady since the mid-19th century, the increasing length of those wars resulted in increasing numbers of wars ongoing at any one time. For example, there were no more than five civil wars underway simultaneously in the first half of the 20th century, while over 20 concurrent civil wars were occurring at the end of the Cold War, before a significant decrease as conflicts strongly associated with the superpower rivalry came to an end. Since 1945, civil wars have resulted in the deaths of over 25 million people, as well as the forced displacement of millions more. Civil wars have further resulted in economic collapse; Burma (Myanmar), Uganda and Angola are examples of nations that were considered to have promising futures before being engulfed in civil wars.

Kenneth Lauren "Ken" Burns (born July 29, 1953) is an American director and producer of documentary films, known for his style of using archival footage and photographs. Among his productions are The Civil War (1990), Baseball (1994), Jazz (2001), The War (2007), The National Parks: America's Best Idea (2009) and Prohibition (2011).

Burns' documentaries have been nominated for two Academy Awards, and have won Emmy Awards, among other honors.

Ken Burns was born in 1953 in Brooklyn, New York City, New York, according to his official website, though some sources give Ann Arbor, Michigan, and some, including The New York Times, give both Brooklyn and Ann Arbor. The son of Lyla Smith (née Tupper) Burns, a biotechnician, and Robert Kyle Burns, at the time a graduate student in cultural anthropology at Columbia University, in Manhattan. Ken Burns' brother is the documentary filmmaker Ric Burns.

Burns' academic family moved frequently, and lived in Saint-Véran, France; Newark, Delaware; and Ann Arbor, where his father taught at the University of Michigan. Burns' mother was diagnosed with breast cancer when Burns was 3, and died when he was 11, a circumstance that he said helped shape his career; he credited his father-in-law, a psychologist, with a signal insight: "He told me that my whole work was an attempt to make people long gone come back alive.". Well-read as a child, he absorbed the family encyclopedia, preferring history to fiction. Upon receiving an 8 mm film movie camera for his 17th birthday, he shot a documentary about an Ann Arbor factory. Turning down reduced tuition at the University of Michigan, he attended the new Hampshire College, an alternative school in Amherst, Massachusetts with narrative evaluations rather than letter grades and self-directed academic concentrations instead of traditional majors. He worked in a record store to pay his tuition.