Besides these protections to the flank, the line itself was very strong. There were hills, hollows, ravines, groves, ledges, fences, cornfields, orchards, stone-walls,--all of which are important in a great battle. Besides all of those natural defenses, General Lee threw up breastworks and rifle-pits to make his line as strong as possible. His line was on the ridge, between the Antietam and the Potomac. There are three stone bridges across the Antietam near where the battle was fought. One of them will be known in history as the Burnside Bridge, for there the troops commanded by General Burnside forced back the Rebel right wing, and crossed the stream. It is on the road which leads from Sharpsburg to the little village of Roherville in Pleasant Valley. A mile north, there is another at the crossing of the Boonesboro' and Sharpsburg turnpike. A half mile above, on the eastern bank, there is a large brick farm-house, where General McClellan had his head-quarters during the battle. Following the windings of the stream, we reach the upper bridge, on the road from Keedysville to Hagerstown. On the western bank are the farms of John Hoffman and D. Miller. There is a little cluster of houses called Smoketown. Traveling directly west from Hoffman's one mile across the fields, we reach the Sharpsburg and Hagerstown pike, near the residence of Mr. Middlekauff. A quarter of a mile farther would carry us to the great bend of the Potomac. But turning south, and traveling the turnpike, we reach the farm-house of Mr. John Poffenberger,[60] a wooden building standing with its gable towards the turnpike. There are peach-trees in front, and a workshop, and a bee-bench. [Footnote 60: Upon the map accompanying General McClellan's Report there are several residences marked Poffenberger; also several marked D. Miller. But the residence here described was the one around which the severest fighting occurred on the right,--Joseph Poffenberger's.] There is a high ridge behind the house, crowned by Poffenberger's barn. Standing upon the ridge and looking west, we behold the turnpike at our feet, a mown field beyond, and fifty or sixty rods distant a cornfield, and a grove of oaks. That cornfield and those oaks is the ground occupied by Jackson's left wing. A few rods south of Poffenberger's is the toll-gate. There a narrow lane runs west towards the Potomac. Another leads southwest, past an old house and barn, winding through the woods, and over the uneven ground where Jackson established his center. There is a grove of oaks between the toll-gate and the farm-house of Mr. J. Miller, a few rods further south. Mr. Miller had a large field in corn on the hillside east of his house at the time of the battle. Standing there upon the crest and looking east, we have a full view of the farm of John Hoffman. Here and on the ridge behind Poffenberger's, Jackson established his advanced line one half of a mile from his main line, west of the turnpike.