navigable pontcysyllte aqueduct, carries the llangollen canal waters across the river dee

across aqueduct arch arched boat boats bridge britain canal cast connects construction copy countryside dee destination ellesmere flow great height heritage iconic iron landmark landscape llangollen location masonry narrow narrowboat nature navigable navigation network outdoors passage pastures people pontcysyllte queduct remote river site space stone stonework structure tops tourism tourist towpath transport travel tree trees unesco vale valley wales water waterway world