I've heard and read about this activity. I even think I've seen it in movies, but this is the first time I've seen such construction on so large a scale. When we visited Lake Ellsworth, we walked up to the dam. Nearby we saw this line in the grass that extended from the woods clear across the grassed area above the dam. Large ants had build a highway through the grass. For ease of movement, everything that impeded their progress had been removed. Grass had been cut off either side of the path and removed. Gravel or leaves that they had to climb over or walk around were likewise removed. If they couldn't pass it in the course of normal walking, it had to go. It was really fascinating, and best of all, they didn't have to wait for federal funding to get the highway done.