Before Charleston was a city, it was a center for commerce—commerce that desperately needed protecting. Whether it was to keep out pirates, the Spanish, and the French, or to keep in slaves, in the early 1700s the original town (about six blocks today) was surrounded by a wall.

The wall wasn’t just a deterrent. It housed dozens of cannons that required serious amounts of gunpowder—all kept in the Powder Magazine that still stands in modern-day Charleston.

Measuring 27 feet by 27 feet, the magazine was built with three-foot thick walls that arched to the ceiling so, should a horrible mistake occur, most of the explosive force would exit through the roof. And to smother the fire, the arches are packed with several tons of sand. Fortunately, the wisdom of the design has never been tested since there’s never been an explosion.

The magazine, which is the oldest surviving public building in the former Province of Carolina, hasn’t held gunpowder since the Revolutionary War. Since then, it’s been a wine cellar, warehouse, print shop, and livery stable, among other things.

Today, The Magazine features guns, uniforms, artifacts and stories from its more than 300-year history, told by enthusiastic docents—including stories of those ruthless pirates we mentioned. You might even get a lesson in firing a Revolutionary-era musket.