To cross a stream, street or valley (in which the delay brought on by a flight of locks at either side could be unacceptable) the valley may be spanned by a navigable aqueduct – a well-known case in point in Wales may be the Pontcysyllte Aqueduct (now a UNESCO https://comprarinstagramviewsreel11098.blogthisbiz.com/44274315/5-easy-facts-about-musica-infantil-described