I’ve worked construction for 31 years, and I’ve never felt the earth give up a secret like that.

The morning started like any other. Dave Kowalski was on the excavator, I was marking utility lines, and the sun was already beating down on the empty field off old Route 9. We were clearing ground for a new shopping complex just outside Arden, Minnesota. The whole crew was grumbling about the heat, about the rock in the soil, about the coffee from the gas station being too weak.