To cross a stream, street or valley (in which the delay caused by a flight of locks at either facet will be unacceptable) the valley might be spanned by a navigable aqueduct – a popular illustration in Wales is the Pontcysyllte Aqueduct (now a UNESCO World Heritage Site) through https://canal-infantil11098.blogaritma.com/35265228/details-fiction-and-canal-infantil