You can almost imagine entering a medieval walled city as you approach Halstead from the north on K-89. Massive gates hang between concrete pillars, and high earthen walls border either side. Are they here to guard the town and the tall grain elevators that appear like castles? It's not quite so dramatic. What you're actually seeing are huge flood prevention structures built in 1994. The gates stand at the bridge entrances over the Little Arkansas River, and will close if the river begins to rise toward flood stage. No medieval mystique, but nonetheless important.