Britannia Bridge is a bridge across the Menai Strait

Menai Strait

The Menai Strait is a narrow stretch of shallow tidal water about long, which separates the island of Anglesey from the mainland of Wales.The strait is bridged in two places - the main A5 road is carried over the strait by Thomas Telford's elegant iron suspension bridge, the first of its kind,...

 between the island of Anglesey

Anglesey

Anglesey , also known by its Welsh name Ynys Môn , is an island and, as Isle of Anglesey, a county off the north west coast of Wales...

 and the mainland of Wales. It was originally designed and built by Robert Stephenson

Robert Stephenson

Robert Stephenson FRS was an English civil engineer. He was the only son of George Stephenson, the famed locomotive builder and railway engineer; many of the achievements popularly credited to his father were actually the joint efforts of father and son.-Early life :He was born on the 16th of...

 as a tubular bridge

Tubular bridge

A tubular bridge is a bridge built as a rigid box girder section within which the traffic is carried. Famous examples include the original Britannia Bridge over the Menai Strait and the Conwy railway bridge over the River Conwy, designed and tested by William Fairbairn and built by Robert...

 of wrought iron

Wrought iron

thumb|The [[Eiffel tower]] is constructed from [[puddle iron]], a form of wrought ironWrought iron is an iron alloy with a very low carbon...

 rectangular box-section spans for carrying rail traffic. Following a fire in 1970 it was rebuilt as a two-tier steel truss arch bridge

Truss arch bridge

A truss arch bridge combines the elements of the truss bridge and the arch bridge. The actual resolution of forces will depend upon the design. If no horizontal thrusting forces are generated this becomes an arch-shaped truss, essentially a bent beam — see moon bridge for an example...

, carrying both road and rail traffic.
The opening of the Menai Bridge

Menai Suspension Bridge

The Menai Suspension Bridge is a suspension bridge between the island of Anglesey and the mainland of Wales. Designed by Thomas Telford and completed in 1826, it was the first modern suspension bridge in the world.-Construction:...

 in 1826, a mile (1.6 km) to the east of where Britannia Bridge was later built, provided the first fixed road link between Anglesey and the mainland.