To cross a stream, highway or valley (wherever the delay brought on by a flight of locks at either facet might be unacceptable) the valley might be spanned by a navigable aqueduct – a renowned example in Wales would be the Pontcysyllte Aqueduct (now a UNESCO Planet Heritage Website) https://donovangnubf.designi1.com/57938981/5-tips-about-urso-fofo-you-can-use-today