You are on a barge cruising along the Mississippi River in Winona Minnesota. The sky is blue and the water is clear on a brisk day in October. As you approach the lock and dam, you notice that the name has a number and letter: 5A. Curiously, you look up why the name includes a letter, which is abnormal for lock and dams along the Mississippi. As you are researching, you learn that engineers made a mistake when adding lock and dams along the river. They placed numbers 5 and 6 too far away from each other, so they had to put an extra in between. It is the only lock and dam along the entire Mississippi that is named this way. The Mississippi River has been used for centuries to transport goods across the United States. These goods are transported in barges, which are more efficient than semi-trucks and trains. As a significant part of American History, lock and dams are the backbone of transportation. Without them, not as many goods would circulate around the United States and certainly not as fast as barges can deliver them.