The Hartland Covered Bridge is the world's longest covered bridge, stretching 390.75 metres across the Saint John River between Hartland and Somerville. Built in 1901 and covered after major repairs in 1921, it is now a National Historic Site of Canada and the town's whole reason for being on most travel maps.
Drive it if traffic allows, but also walk the separate pedestrian side. The slow wooden tunnel, the river views at either end, and the strange scale of a covered bridge this long are what make Hartland worth the detour.