This period of economic growth, which was ushered in by the introduction and adoption of the steamboat, was one of the greatest ever experienced in the United States. Around 1815, steamboats began to replace barges and flatboats in the transport of goods around the United States. Prior to the steamboat, rivers were generally only used in transporting goods from east to west, and from north to south as fighting the current was very difficult and often impossible. Non-powered boats and rafts were assembled up-stream, would carry their cargo down stream, and would often be disassembled at the end of their journey; with their remains being used to construct homes and commercial buildings.