It has the same purpose as any other bridge, to allow passage across a river or another natural obstacle such as a ravine. Bridges usually carry a road, a railway line, pedestrians or a combination of these across a river.
There are two bridges over the Firth of Forth. The rail bridge and the road bridge.
The Forth Road Bridge (as the name suggests) is a motor vehicle bridge (as well as a cycle and pedestrian bridge) which spans the Firth of Forth.
There is many different types of makes; Steel Iron..
The Forth road and rail bridges span the Firth of Forth, which is the estuary of the River Forth in Scotland near the city of Edinburgh.
The Chesapeake Bay Bridge-Tunnel
The Forth Bridge spans over the Firth of Forth in Scotland. It carries rail traffic between Edinburgh at South Queensferry and Fife at North Queensferry.
The Firth of Forth bridge in Scotland is AA very famous truss bridge. Does that help?
They're in Scotland, between Midlothian and Fife. The railway bridge was opened in 1890 and the road bridge in 1964.
Edinburgh, the capital of Scotland, is on the Firth of Forth.
The Antonine Wall is between Firth of Forth and Firth of Clyde.
The Firth of Forth was not "built" - it was created by a glacier in the last ice age. A firth is the lowland Scots word for an inlet from the sea, much the same as the Scandinavian word 'fjord' - in this case the estuary of the River Forth. I think you probably mean "When was the Forth (Rail) Bridge built?", and the answer to that is between 1883 & 1890. It was joined by a parallel road bridge in 1964. The railway bridge - still a hugely impressive structure - was the engineering wonder of its age, though it was achieved at the cost of many workers' lives. It is seen in a number of old films - most famously in both the 1935 & 1959 versions of "The 39 Steps".
At the time that the bridge was built, technology wasn't good enough to build a tunnel of the necessary length.