The longest sea bridge in the world at 20.2 miles long is the Donghai bridge that links Shanghai to Yangshan in China. A bridge from either Northern Ireland or the Republic of Ireland would have to be even longer than that. In 2007, a 21-mile rail bridge was proposed between Galloway, Scotland, to Belfast, Northern Ireland. The idea would have trains running from Dublin, through Belfast, over the sea to Scotland, and then down railways into London... "Four main routes have been proposed. Two run from Scotland to Northern Ireland - Campbeltown to County Antrim, or Stranraer to Belfast. Two...