The reverse (back) design of the Sacajawea dollar features an eagle flying over a mountain and forest. The eagle is the most widely known national symbol of the United States, and its soaring above the mountains and forests evokes the spirit of freedom, adventure, and conquest that characterized America's westward expansion in the early 19th century. The image of the eagle was inspired by early United States coins such as the Draped Bust dollar and the Flying Eagle cent.