To cross a stream, street or valley (the place the delay brought on by a flight of locks at either facet might be unacceptable) the valley may be spanned by a navigable aqueduct – a well-known case in point in Wales is definitely the Pontcysyllte Aqueduct (now a UNESCO https://edgarzfkns.blogsvirals.com/36106094/the-fact-about-musica-infantil-that-no-one-is-suggesting