Shiloh National Military Park is one of the most expansive and well preserved civil war battlefields in the country. This battlefield, and the Union victory here, was important to the Civil War. But considering what unfolded here 155 years ago, you may just feel the echoes of the past giving you chills. On April 6 and 7 of 1862, one of the major engagements of the Civil War unfolded at Shiloh. Confederates launched a surprise attack on Union forces. Confederates were unable to hold their positions, were forced back, and the Union won the battle. The battle was violent which led to 23,000 casualties. At the time this was the bloodiest battle in American history.