Pick one category for the following text. The options are - company, educational institution, artist, athlete, office holder, mean of transportation, building, natural place, village, animal, plant, album, film or written work. Main Line of Public Works - The Main Line of Public Works was a state funded and built railroad and canal system across southern Pennsylvania between Philadelphia and Pittsburgh that included the Philadelphia and Columbia Railroad the Allegheny Portage Railroad and the Pennsylvania Canal system created in response to the advent and success of the Lehigh Navigations and the Erie Canals.
A:
Natural Place