Rideau Canal. In winter the Rideau Canal becomes the world's longest skating rink, stretching 7.8 km (4.6 miles) from the National Arts Centre to Dows Lake. Skates can be rented and sharpened across from the National Arts Centre, on the canal by Fifth Avenue. Wooden sleighs can also be rented. Along the route are warm-up shelters and food concessions. Call for a recorded message detailing daily skating conditions. Ottawa, ON. 613/239–5234.