Question: what historic building in Washington, D.C. is located near the canal who's primary cargo is coal
Sentence (from "Chesapeake and Ohio Canal"): The Chesapeake and Ohio Canal, abbreviated as the C&O Canal and occasionally called the "Grand Old Ditch," operated from 1831 until 1924 along the Potomac River from Washington, D.C., to Cumberland, Maryland.
Relevant evidence: No