My daughter and I go hiking most Sundays shortly after a late breakfast. Yesterday’s hike took us about a mile up a narrow canyon near my home in Colorado, where the remnants of a long-abandoned concrete dam block half of the North St. Vrain River. This dam was started in the 1930s by the Colorado branch of the Ku Klux Klan, which apparently ran out of money well before any water was impounded.

The Klan is gone but the concrete remains, looking nowhere near its 80 years. It seems an apt testament to both the bad ideas the Klan espoused and the durability and sustainability of concrete. Even the 500-year flood of two years ago, which roared through that valley, doesn’t seem to have made a dent in the old dam. It’s worth remembering that the concrete we place today will be around long after we’re gone, so it makes sense to do it right. If the Klan could do it so can we!