(STARDIA POST) – When a Michigan man was tearing down his home's back landing, he discovered 160 bowling balls beneath the stairs.

David Olson said he noticed a spherical object in the sand behind some cinder blocks while dismantling the stairs behind his Muskegon home on July 1. "That was one of the bowling balls. I didn't think much of it. I was kind of assuming maybe there were just a couple in there to fill in," Olson told the Detroit Free Press. "The deeper I got into it, the more I realized it was just basically an entire gridwork of them making up the weight in there."

In the days that followed, Olson said he continued to dig and discovered 160 bowling balls. The house was built in 1959, when the Brunswick Bowling Products factory in Muskegon was still in operation, producing bowling balls, pins, and other products before the company relocated its operation to Mexico, according to the homeowner.