Crossing the powder-blue bridge spanning the Potomac River at Point of Rocks, Maryland, I feel like I’ve time-warped to another century. With my husband and two children in tow, we have left behind the bustling Virginia suburbs of Washington, D.C., to stay in a historic lockhouse along the C&O Canal. For one weekend at least we hope to experience what life was like for a 19th-century lock tender and his family, whose livelihood was tied to the daily rhythms of moving boats and goods. If history had gone in a different direction, however, our stay would have been impossible.