Just off the South Carolina coast and almost a stone's throw from Charleston, there's an island fortification rich with American history. This man-made structure in the middle of Charleston Harbor is credited with having had the first shots of the Civil War fired upon it 156 years ago. The history of this historic fort is fascinating.

But let's start with this little nugget of information.

When you visit this fort today, you'll find several of what appear to be unexploded shells embedded within the walls!

If we back up just a bit and take a look at this map for reference, we can see why this fort, dubbed Fort Sumter, was built where she was.

Strategically, she sits at the entrance to the Charleston harbor and was intended by the federal government to provide protection after the War of 1812.

By the start of the Civil War the construction of this grand fort wasn't yet complete. But exactly six days after South Carolina seceeded from the Union, U.S. Army Major Robert Anderson moved his federal troops from Fort Moultrie into Fort Sumter staking a claim to it and the Charleston Harbor -- on behalf of the federal government. The date was December 26, 1860.

By April 1861, Confederate forces were eager to have control of the fort and this important harbor in the South. Afterall, it was protecting a city in a state that was no longer part of the Union. Also by this time, rumors were afoot that the troops occupying Fort Sumter were going to run out of food within days. On April 12, 1861 Confederate forces opened fire on the fort, firing relentlessly for 34-hours before the Union troops surrendered.

The Confederacy would have control of Fort Sumter for the next four years. But they had to continuously defend their holding.

This photo was taken in 1864. The interior of Fort Sumter shows extensive damage from bombardments that began by the Union troops in 1863. Yet, despite a loss of men, a loss of weapons, and massive structural damage, the last Confederate commander of Fort Sumter, Major Thomas A. Huguenin, never surrendered Fort Sumter. (By the way, Major Huguenin was a graduate of The Citadel, The Military College of South Carolina.)

In the end, it was General William T. Sherman's march into Charleston that forced the Confederates to evacuate Charleston. And the Union troops raised their flag in Fort Sumter again on February 22, 1865.

In ruins after the Civil War, Fort Sumter underwent some renovations including leveling off the top, making the fort much shorter than it originally was.

And today, it's a National Monument, maintained and operated by the National Park Service.

You can take a tour boat over to this national treasure and then you can seek out the unexploded shells still in the walls.

There are several to be found.

And each one likely represents lives that were spared inside this island fortification that's so rich in American history off the coast of South Carolina.

Have you explored Fort Sumter in person and did you see these unique artifacts embedded in the walls of this historic island fortress? We'd love to know and hear about your adventure in our comments!

To learn about Fort Sumter's neighboring fortress in the Charleston Harbor, read all about the Lost National Park In South Carolina.