Here’s What Happens When You Find a (Potentially Explosive) 19th Century Cannonball In Your House

And why this family had the military show up at their door.

— -- At the beginning of the 2014 holiday season, Rula Norregaard and her family wanted to light a fire in their 19th century house in the Georgetown neighborhood of Washington, D.C.

After 18 years of simply using candles they decided to splurge and have the fireplace cleaned out and inspected by a professional cleaning crew.

And that’s when everyone heard a thud.

“I came and I saw they were holding a cannonball, and we were just thrilled to have it,” Norregaard told ABC News. “I mean we didn’t think much of it. To me it was a heavy piece of lead.”

Rula’s kids showed it off to their friends, it sat in their living room and her husband even used it as a paper weight. The heavy, lead cannonball became a novelty item to show guests and friends. The idea of it being dangerous never crossed the family’s mind.

Until this Christmas.

At a party at their house, a physicist friend of theirs began inspecting the ball. He strongly encouraged the family to call the authorities, fearing it could still explode.

“I didn’t call 911, I called 311 and they thought it was something very dangerous and they called everybody,” Norregaard said.

Now Norregaard says she would love to get the cannonball back: “Now it has a story.”

No word yet on whether the cannonball contained explosives.