On this evening 150 years ago, the town of Gettysburg, Pa. (population 2,400) was left with nearly 8,000 bodies and 3,000 horse carcasses rotting in the summer sun — so many that townspeople gagged at the stench.

After three days of fighting, the Union had won the bloodiest battle of the Civil War, but they lost 2,155 soldiers and more than 14,000 others were wounded. More than 5,000 were captured or went missing.

Confederate casualties were far greater. Nearly a third of Gen. Robert E. Lee’s general officers were killed, wounded or captured.

Despite three days of heavy fighting, only one civilian was killed. Jenny Wade was struck down by a stray bullet as she worked inside her house.

The Battle of Gettysburg was a decisive victory for the Union. It stopped the Confederate invasion of the North and forced Lee’s army to withdraw to Virginia.