Ottawa sits at the confluence of three major rivers: the Ottawa River, the Gatineau River and the Rideau River. The Ottawa and Gatineau rivers were historically important in the logging and lumber industries and the Rideau as part of the Rideau Canal system for military, commercial and, subsequently, recreational purposes. The Rideau Canal (Rideau Waterway) first opened in 1832 and is  long. It connects the Saint Lawrence River on Lake Ontario at Kingston to the Ottawa River near Parliament Hill. It was able to bypass the unnavigable sections of the Cataraqui and Rideau rivers and various small lakes along the waterway due to flooding techniques and the construction of 47 water transport locks. The Rideau River got its name from early French explorers who thought the waterfalls at the point where the Rideau River empties into the Ottawa River resembled a "curtain". Hence they began naming the falls and river "rideau" which is the French equivalent of the English word for curtain. During part of the winter season the Ottawa section of the canal forms the world's largest skating rink, thereby providing both a recreational venue and a  transportation path to downtown for ice skaters (from Carleton University and Dow's Lake to the Rideau Centre and National Arts Centre).