Engineer Rob Bell sets out on a journey to discover how six of Britain's most stunning bridges were designed and built. Completed in 1890, the Forth Rail Bridge now carries around 200 trains every day. The last of the great Victorian engineering triumphs, it has grown to symbolise Scotland as much as Edinburgh Castle, bagpipes or kilts. But, as Rob learns, this incredible engineering achievement was born from the tragedy of the 1879 Tay Bridge disaster, and 73 deaths were connected with its construction and immediate aftermath.