What is the significance of The Battle of Gettysburg?

The Battle of Gettysburg is considered the turning point
in the war, and the point at which the outcome was inevitable. General Robert E. Lee had
previously invaded the North in hopes of securing recognition from England and France
for the Confederacy; but was defeated at the battle of Antietam (Sharpsburg.) He invaded
the North again after a successful campaign at Shenandoah in hopes of bringing pressure
on Northern politicians to end the war on favorable terms. During the final days of the
battle, Confederate Vice President Alexander Stephens approached the lines under a flag
of truce, presumably to discuss prisoner exchanges; although there is some speculation
he may have also hoped to discuss peace. However, after word of the Union victory,
President Abraham Lincoln refused to allow Stephens to cross Union lines.  The battle
destroyed any hope of aa Confederate victory, let alone recognition from Europe. Henry
Adams, son of John Quincy Adams, commented after the
battle:

The
disasters of the rebels are unredeemed by even any hope of success. It is now conceded
that all idea of intervention is at an
end.