Police reported that a technical issue caused a tank owned by the British Army to veer off its course, running amok until a fence belonging to Ulrich Tilsner stopped it.
Tilsner was about to leave to meet his granddaughter when he heard the sound of his fence being taken out.
"My Opa (grandpa) telephoned and said 'I'm coming somewhat later, I have a tank in my garden'," Stefanie Ney told the Neue Westfälische newspaper.
Ney then rushed to her grandparents to find quite a scene.
"There was a tank in the hedge and soldiers standing everywhere and our dog was barking like crazy," she said. "My Oma (grandma) was completely in shock."
Magdalene Tilsner likened the crash to a bomb going off.
The tank occupants walked away from the incident unscathed and while the Tilsner's house was untouched, police said part of its wall would have to be replaced, as well as several plants, with damages estimated around €1,000.
It took police and the British Army several hours to remove the faulty tank.
A drive chain suffered the technical disturbance that caused the crash.
According to police, the tank is part of a military driving school belonging to the Paderborn Garrison of the British Army based not far from where the accident happened.
"People in Paderborn are not shocked when they see a tank," a police spokesperson told dpa.