To cross a stream, street or valley (the place the delay because of a flight of locks at possibly aspect can be unacceptable) the valley could be spanned by a navigable aqueduct – a famous illustration in Wales is definitely the Pontcysyllte Aqueduct (now a UNESCO Environment Heritage Web-site) https://johnnydjpwa.blogolize.com/the-definitive-guide-to-urso-fofo-76138302