To cross a stream, highway or valley (wherever the delay attributable to a flight of locks at possibly side could be unacceptable) the valley may be spanned by a navigable aqueduct – a well-known example in Wales is the Pontcysyllte Aqueduct (now a UNESCO Environment Heritage Internet site) across https://knoxtbeim.ampedpages.com/a-review-of-canal-infantil-64021579