Complex sentence: These are just some of the many historical sites that follow along the Difficult Run.Old Georgetown Pike Highway, which parallels Difficult Run, is known as a National Historic landmark because the route it follows was first used by Indians and then after by them, by colonists.
Split into simpler sentences: These are just some of the many historical sites that follow along the Difficult Run. This highway is known as a National Historic landmark because the route it follows was first used by Indians and then after by them, by colonists.