Challenge of the century: What exactly is involved in digging a tunnel from Spain to Morocco? - The incredible PS6bn tunnel linking Africa to Europe dealt fresh blow over terrain concerns - The incredible PS5.9bn underwater tunnel connecting two European countries - German tunnelling specialists 'awarded contract to assess feasibility of Spain to Morocco underwater train' - reports - The tunnel linking two pretty European countries set to reopen after PS207m project - Norway's underwater tunnel: Changing the way we travel - $20 trillion tunnel that could link New York and London in an hour - Norway building world's longest, deepest undersea road tunnel - World's longest and deepest underwater tunnel, will connect Denmark and Germany - Metro Vancouver digs water tunnel designed to withstand 'the big one' under Fraser River