To cross a stream, street or valley (in which the delay caused by a flight of locks at possibly aspect can be unacceptable) the valley could be spanned by a navigable aqueduct – a popular instance in Wales will be the Pontcysyllte Aqueduct (now a UNESCO World Heritage Web https://dantewchzq.blog-kids.com/37441344/musica-infantil-can-be-fun-for-anyone