To cross a stream, highway or valley (where by the hold off attributable to a flight of locks at both side would be unacceptable) the valley is often spanned by a navigable aqueduct – a well known case in point in Wales would be the Pontcysyllte Aqueduct (now a https://cristianlmgzr.blog2freedom.com/37176735/5-essential-elements-for-musica-infantil