The UK wants to build one of the world's most ambitious bridges

Right now, the UK has a reputation more for burning bridges than building them. But its plans to build a fixed sea link between Scotland and Ireland might well be one of history's most challenging engineering projects.

(CNN) — At the western edge of Europe lie two little islands with a complex past. Ireland and Britain are just 12 miles apart at the Irish Sea's narrowest point, but waters run deep here -- in every sense. For the past century, Ireland's northeast corner has been part of the United Kingdom of Great Britain and Northern Ireland.