To cross a stream, road or valley (exactly where the delay brought on by a flight of locks at either facet might be unacceptable) the valley might be spanned by a navigable aqueduct – a renowned instance in Wales may be the Pontcysyllte Aqueduct (now a UNESCO Globe Heritage https://messiahbimru.therainblog.com/35935750/fascination-about-musica-infantil