Complex sentence: This stifled trade across the lower Susquehanna in colonial Pennsylvania and Maryland, spurring the 1730 opening of the historic Wright's Ferry and the first Columbia-Wrightsville Bridges, once believed to be the longest covered bridges in the world.
Split into simpler sentences: This stifled trade across the lower Susquehanna in colonial Pennsylvania and Maryland. Later the first Columbia-Wrightsville Bridge was built, once believed to be the longest covered bridges in the world.