Other emerging towns challenged Pittsburgh. In 1818, the first segment of the National Road was completed, from Baltimore to Wheeling, bypassing Pittsburgh. This threatened to render the town less essential in east-west commerce. In the coming decade, however, many improvements were made to the transportation infrastructure. In 1818, the region's first river bridge, the Smithfield Street Bridge, opened, the first step in developing the "City of bridges" over its two rivers. On October 1, 1840, the original Pennsylvania Turnpike was completed, connecting Pittsburgh and the eastern port city of Philadelphia. In 1834, the Pennsylvania Main Line Canal was completed, making Pittsburgh part of a transportation system that included rivers, roads, and canals.