The canals of Europe were constructed mostly in the 17th, 18th, and first half of the 19th centuries for transporting commercial goods. Canals often connected navigable sections of different rivers or were constructed to bypass shallow or otherwise unnavigable sections of larger rivers. Prior to canals, the only available transport for goods was via wagons on poorly constructed and maintained roads. Today, the canals are used largely for recreational purposes and narrowboats. The narrowboats often have living quarters and are used by vacationers and tourists.