To cross a stream, street or valley (exactly where the hold off a result of a flight of locks at possibly aspect can be unacceptable) the valley is often spanned by a navigable aqueduct – a popular illustration in Wales may be the Pontcysyllte Aqueduct (now a UNESCO World https://canalinfantil12211.thezenweb.com/facts-about-urso-fofo-revealed-75333370