Tenby's giant cistern
In the centuries when ships sailed to and from Tenby harbour, build-up of sand deposited by each tide would have made the water too shallow were it not for an ingenious flushing system built in the early 17th century. A long wall ...
was built to impound water at high tide which would be released at low tide to wash sediment from the harbour. The structure was rebuilt at various times. The harbour sluice fell out of use long ago but you can still walk along the top of its wall. For more about the sluice - and a drawing showing its full length in 1817 - use your smartphone to scan the HistoryPoints QR codes on the posts at either end of the sluice wall. Or click here