To cross a stream, street or valley (exactly where the delay because of a flight of locks at both side could be unacceptable) the valley is usually spanned by a navigable aqueduct – a famed instance in Wales is the Pontcysyllte Aqueduct (now a UNESCO World Heritage Website) through https://edwinwhlpt.blogacep.com/42514590/facts-about-urso-fofo-revealed