The Welland Canal is a ship canal in Ontario, Canada, and part of the St. Lawrence Seaway and Great Lakes Waterway. The canal traverses the Niagara Peninsula between Port Weller on Lake Ontario, and Port Colborne on Lake Erie, and was erected because the Niagara River—the only natural waterway connecting the lakes—was unnavigable due to Niagara Falls. The Welland Canal enables ships to ascend and descend the Niagara Escarpment, and has followed four different routes since it opened.