There’s a secret under the Detroit River.And no… it’s not Jimmy Hoffa. Every time we take a cruise down the river, we glide over something most people never even think about a hidden world beneath the surface. Down there are old shipping channels carved by decades of freighters, forgotten foundations from long-gone industries, and the quiet hum of the river’s currents reshaping the shoreline one grain of sand at a time.Captains talk about it in that half-whisper sailors use when they’re not sure