The island of Cape Breton is linked to the mainland by the Canso Causeway which was constructed in 1955. This is the deepest causeway in the world at 217 feet. On the Cape Breton side of the causeway, a swing bridge permits small vessels to pass from the Gulf of St. Lawrence into the Atlantic Ocean. On my return to the mainland I had to wait along with other cars as a sailboat with its tall mast made it's way across.