The Menai suspension Bridge span the Menai Strait between Anglesey and the Welsh mainland.It was built by Thomas Telford from 1819-1826 and spans 175 m (579 ft).The roadway is suspended by 16 chain cables,made of 935 iron bars each,that carry the weight to the two huge concrete towers.It was by far the longest suspension bridge to be built until that time.Fourteen years later,Robert Stephenson built the Britannia Bridge nearby to carry a new railway line that ran to the port of Holyhead.The longest suspension bridge in Britain is the Humber Bridge.Completed in 1981,it is 2,200 m(6,770 ft) long,with a cen tral span of 1,410 m (4,700 ft).