Question

How did the three day Battle of Gettysburg begin?

Answer 1

Hint: It was during the American Civil War, Union and Confederate forces fought the Battle of Gettysburg in and around the town of Gettysburg of Pennsylvania from $1^{st}$ of July to 3rd of July, 1863. The Battle of Gettysburg is generally considered as the turning point of the American Civil War.

Complete answer:
The Battle of Gettysburg, a major battle of the American Civil War began as an engagement between units of the Army of the Potomac under Union Major General George Meade (North) and the Army of Northern Virginia under Confederate General Robert E. Lee (South). Large number of casualties happened as a result on the first day itself.
Robert E. Lee’s Confederate Army got victory over the Union Army at Chancellorsville in May 1863. This tempted Lee to go on and invade the North.
President Abraham Lincoln lost confidence in the Union Army of the Potomac’s commander, Joseph Hooker, who was reluctant to confront Lee’s army after the defeat at Chancellorsville. Major General George Gordon succeeded Hooker on 28th June. The new commander of the Union Army immediately ordered the pursuit of Lee’s army which by then had crossed the Potomac River into Maryland and marched on into southern Pennsylvania.
Lee planned to assemble his army in the crossroads town of Gettysburg, upon learning that the Union Army was on its way. Both armies headed toward Gettysburg and the Confederate army were able to drive the outnumbered defenders back through town to Cemetery Hill, situated a half mile to the south. Thus began the first day of the three day Battle of Gettysburg.
Finally, the Union army of the North won the Battle of Gettysburg.

Note: On November 19, 1863, a speech was given by the US President Abraham Lincoln at the dedication of the National Cemetery at Gettysburg, Pennsylvania, in and around where the Battle of Gettysburg took place and this speech is known popularly as the Gettysburg Address.