Elfstedentocht, a 200 km distance skating race of which the tracks leads through the 11 different cities in Friesland which is a northern province of the Netherlands. Skate tracks on natural ice are maintained by the towns and communities, who take care of the safety of the tracks. Ice cross downhill tracks Ice cross downhill, (formerly known as "Red Bull Crashed Ice" or "Crashed Ice"), is a winter extreme sporting event involving direct competitive downhill skating. Skaters race down a walled track which features sharp turns and high vertical drops. Trails Rideau Canal Skateway An example of an ice skating trail, or "rink", is the Rideau Canal Skateway in Ottawa, Ontario, Canada, estimated at and long, which is equivalent to 90 Olympic-size skating rinks. The rink is prepared by lowering the canal's water level and letting the canal water freeze. The rink is then resurfaced nightly by cleaning the ice of snow and flooding it with water from below the ice. The rink is recognized as the "world's largest naturally frozen ice rink" by the Guinness Book of World Records because "its entire length receives daily maintenance such as sweeping, ice thickness checks and there are toilet and recreational facilities along its entire length". Longest trail The longest ice skating trail is in Invermere, British Columbia, Canada, on Lake Windermere Whiteway. The naturally frozen trail measures . Combined Outdoor ice skating activities and competitions involving a goal of distance travel for recreation, exercise, competition and adventure, can involve frozen lakes, rivers, and canals. Tour skating The sport and recreational activity, Tour skating ( "Nordic skating" in North America), is strictly an outdoor activity for ice skaters. Nordic skating originated during the 1900s in Sweden. Ice skaters traverse naturally frozen bodies of water, which sometimes, but not always, includes interconnected ice trails as well as frozen ponds, lakes, and even marsh areas. Tour skaters use a special ice skate with long blades. Elfstedentocht (Eleven cities tour) The Elfstedentocht (Eleven Cities Tour) is a long-distance tour skating event on natural ice, almost long, which is held both as a speed skating competition (with 300 contestants) and a leisure tour (with 16,000 skaters). It is the biggest ice-skating tour in the world and held in the province of Friesland in the north of the Netherlands. The event leads past all eleven historical cities of the province and is held at most once a