The Rideau Canal in Canada shares two similarities with the Kiel Canal in Germany. The Kiel Canal was constructed primarily for military reasons – to enhance the mobility of the German Imperial Fleet between the Baltic Sea and the North Sea. The Rideau Canal was built to serve as a military lifeline between Montreal (and the rest of Lower Canada) and Kingston (and the rest of Upper Canada) in the event of invasion by the United States. The United States had (albeit without great success) invaded Canada during the American Revolution and again during the War of 1812. The rapids along the St. Lawrence River upstream from Montreal greatly impeded military and commercial traffic by water between Lower and Upper Canada. In addition, the US State of New York bordered a stretch of the river, making it highly vulnerable to military blockade. A proposal was made to construct a canal from the Ottawa River, at Ottawa, Ontario to Kingston, Ontario on Lake Ontario. The Ottawa River flowed into the St. Lawrence just upstream from Montreal. A number of small rivers and lakes existed between Ottawa and Kingston, lacking only a series of connections to create a continuous waterway. Construction of the manmade channels and locks began in 1826 and was completed, at significant financial and human cost, in 1832. The Rideau Canal proved to be an immediate economic boost. Heavy cargoes could now be transported at relatively low cost between Lower and Upper Canada. In addition, settlers and immigrants now had easier access to the interior portions of Canada. In these respects, the Rideau Canal did for Canada what the Erie Canal did for the United States. By 1849, however, new locks on the St. Lawrence made that route easier than it had been. In addition, the threat of invasion by the United States largely faded, eliminating the military aspect of the Canal. Thus, the Rideau Canal today has no significant military traffic, as is also true of the Kiel Canal. The Rideau Canal, though, is highly popular with Canadian recreational boaters. It remains operational and retains its original route (unlike the Erie Canal, which experienced some minor re-routing over the years). The Rideau Canal is now a National Historic Site, administered by Parks Canada. Many of its original structures, including locks, blockhouses, dams, and weirs, are still in operation. It is the oldest continuously operated canal system in North America and has been designated as a UNESCO World Heritage Site.