In the late 19th century, Cabin John was renowned for its scenery and climate, drawing visitors from distant places for fishing, bird-watching, bicycling along Conduit Road, and stays at the opulent Cabin John Bridge Hotel as relief from Washington’s malarial summers. Before it became a destination for pleasure, people came in the 1820s to build the Chesapeake and Ohio Canal, then the nation’s most ambitious public works project, and the area known as Cabin John was called Seven Locks by canal builders and boatmen. In the 1850s, when Washington needed a secure source of fresh water, U.S. Army engineers built the Union Arch to carry an aqueduct across the deep Cabin John Creek valley. These two unprecedented engineering projects, the canal and the aqueduct, first defined Cabin John as a distinct location, and the hotel became the first outpost in the development of the community. The hotel later declined and was destroyed by fire in 1931, and part of the creek valley was paved over in the 1960s, but the Cabin John Bridge still supplies water to Washington and the C&O Canal is now a National Park. The canal has more switch locks in the vicinity of Cabin John than any other place on its 185-mile waterway, rising high above the river here to reach the level of an old streambed and creating a community of lockkeepers and a center of activity linked to local farms and commerce by Seven Locks Road. Also called the Union Arch Bridge, the Cabin John Bridge encloses a ten-foot-diameter brick aqueduct that has supplied drinking water to Washington since 1863, and when completed it was the longest stone arch in the world.