To cross a stream, street or valley (the place the delay brought on by a flight of locks at both side will be unacceptable) the valley may be spanned by a navigable aqueduct – a renowned illustration in Wales may be the Pontcysyllte Aqueduct (now a UNESCO Earth Heritage https://canal-infantil05936.win-blog.com/17925336/considerations-to-know-about-musica-infantil