I think that the American expansion of the late 1800s and early 1900s shared some similarities with European Expansion about four centuries earlier. On one hand, material interests drove both. American industry helped to drive the expansion. The laying down of railroad, the prospect of more wealth, and the idea of that which is unclaimed can be claimed for profit helped to drive American expansion both internally and internationally. In much the same way, the Age of Exploration was commenced for the search of "riches" and the conquest that would yield more wealth. Another similarity is that both sought to expand the world in which we live. The Age of Exploration created a new vision of the world, one that was not only centered on Europe but incorporated new places into the schematic and human consciousness. In much the same way, the search of expanding the frontier helped to drive American Expansion. When the frontier was reached with the ocean, the desire the expand moved globally with invasion of other nations and claiming of foreign territory. Finally, like the Age of Exploration, real and disparate wealth collections emerged. There were people who were extremely wealthy, but even more who were dispossessed and rendered powerless.