A hike along the Chesapeake & Ohio Canal and to the Paw Paw Tunnel near Oldtown, Maryland was on the agenda recently for Alexandria, Va., photographer Jeff Olson and his wife, Joanne Plager Burke Olson. The C&O Canal, occasionally called the “Grand Old Ditch,”operated from 1831 until 1924 along the Potomac River from Washington, D.C., to Cumberland, Md. The canal’s principal cargo was coal from the Allegheny Mountains. Construction on the 184.5-mile canal began in 1828 and ended in 1850 with the completion of a 50-mile stretch to Cumberland. Rising and falling over an elevation change of 605 feet, it required the construction of 74 canal locks, 11 aqueducts to cross major streams, more than 240 culverts to cross smaller streams and the 3,118-foot Paw Paw Tunnel. The Paw Paw was built to bypass the Paw Paw Bends, a 6-mile stretch of the Potomac containing five horseshoe-shaped bends. The town, the bends, and the tunnel take their name from the pawpaw trees that grow prolifically along nearby ridges. It was built by Irish laborers, miners from England and Wales and German masons from Pennsylvania.