2. The Rideau Canal, Canada
Over 200 kilometres in length, this waterway joins the Canadian cities of Ottawa, on the Ottawa River, and Kingston, on Lake Ontario. Operated by Parks Canada, the canal encompasses sections of the rivers, Rideau and Cataraqui, along with a few lakes. Originally built with military purposes in mind, today it is mainly used for boating and was designated as a World Heritage Site in 2007.