I had not planned to stop in Pringle, South Dakota. We were driving west through the Black Hills to take a day trip to Wyoming when … I spotted it — a large sculpture made entirely of bicycles, welded together on the roadside outside of town, going nowhere and completely magnificent. We pulled over. My kids ran through its arches and tunnels. We took pictures. We left 10 minutes later having seen something none of us expected. That stop set the tone for the next two days. Just off I-90 near Sundance, Wyoming, I pulled off at a spot I'd found in the Atlas Obscura database : the Quaal Windsock — a 1950s Beechcraft Twin Bonanza airplane, 45-foot wingspan, mounted on a 70-foot pole above the highway. Mick and Jean Quaal loved the old plane but couldn't justify the $200,000 it would have cost to restore it to flying condition. So instead, they put it back in the sky another way. It pivots with the wind. The propellers still spin. We stood there and watched it turn for a while, and then we got back in the car.…