The Rideau Canal is the only operational nineteenth-century canal system in North America engineered for steam-powered vessels, and the only one designed primarily for military logistics rather than trade. Completed in 1832 under Colonel John By of the Royal Engineers, the 202-kilometre waterway connected the Ottawa River to Lake Ontario with forty-seven hand-operated locks and fifty-two dams, a feat of surveying and masonry that cost the lives of more than a thousand workers, many from malaria in the mosquito-dense lowlands south of the capital. By's original engineering drawings, held in the Library and Archives Canada, show a precision rare for the era: lock chambers dimensioned to the inch, slope calculations rendered in copperplate on linen. The canal never saw the military traffic it was built for—Britain and the United States avoided further conflict after 1814—but it opened the interior of Upper Canada to settlement and commerce, transforming Ottawa from a timber camp into a parliamentary city. Today the Rideau Canal bisects downtown Ottawa, its still water reflecting the copper roofs of the Parliament Buildings and the neo-Gothic tracery of the Château Laurier. In winter the canal becomes the world's largest naturally frozen skating rink, a seven-point-eight-kilometre corridor drawing half a million skaters each season. In the navigation months—mid-May through mid-October—pleasure craft and tour boats traverse the same stone-walled lock chambers that steam tugs once hauled timber barges through. UNESCO designated the canal a World Heritage Site in 2007, citing its demonstration of early industrial slackwater technology and its intact hand-cranked lock mechanisms, still operated by Parks Canada staff in period uniform. The waterway remains the engineering spine of the capital, its nineteenth-century infrastructure embedded in a living city. A rideau canal cruise ottawa tour departs from the Ottawa Locks at the canal's northern terminus, where the waterway descends eight consecutive chambers to meet the Ottawa River, a combined drop of twenty-four metres. Electric-powered sightseeing vessels glide south past the National Arts Centre and the Rideau Centre shopping complex, then under the Laurier Avenue Bridge—one of five road crossings in the downtown corridor—before reaching Dow's Lake, a man-made reservoir dredged in the canal's construction and now ringed with boathouses and walking trails. Commentary onboard traces the canal's role in shaping federal architecture, the placement of embassies along its western bank, and the seasonal rhythms of lock operation. The canal's flat water and urban setting make it accessible to all mobility levels, with vessels offering shaded cabin seating and open-air upper decks. Ottawa boat cruises operate daily from spring through autumn, with evening departures timed to catch the copper roofs of Parliament Hill lit by the descending sun over the Gatineau Hills.