To cross a stream, highway or valley (wherever the hold off brought on by a flight of locks at both facet could be unacceptable) the valley could be spanned by a navigable aqueduct – a well-known case in point in Wales is definitely the Pontcysyllte Aqueduct (now a UNESCO https://musicainfantil67765.blognody.com/41595757/5-easy-facts-about-musica-infantil-described