Thomas Telford was assigned the task of improving the route from London to Holyhead, and one of the key improvements was his design of the suspension bridge over the Menai Strait between a point near Bangor on the mainland and the village of Porthaethwy (which is now also known as Menai Bridge) on Anglesey. The design of the bridge had to allow for Royal Navy sailing ships 100 feet (30 m) tall to pass under the deck at high water slack tide, and no scaffolding was allowed during construction as that would have broken the rule.
Construction of the bridge began in 1819 with the towers on either side of the strait. These were constructed from Penmon limestone and were hollow with internal cross-walls. Then came the sixteen huge chain cables, each made of 935 iron bars that support the 176-metre (577 ft) span. To avoid rusting between manufacture and use, the iron was soaked in linseed oil and later painted.The suspending power of the chains was calculated at 2,016 tons and the total weight of each chain was 121 tons. The bridge was opened to much fanfare on 30 January 1826 and reduced the journey time from London to Holyhead from 36 to 27 hours, a saving of 9 hours.
