Blackout hits Europe: Millions left in dark, trains stuck in tunnels / More tunnels could be built in UK city after PS2.2bn project part of Boris Johnson's vision / Mysterious tunnels discovered beneath station in quaint UK city with intriguing past / The UK's secret PS120m 'James Bond' tunnels running underneath major city / Huge PS13m plan to transform abandoned UK tunnel into Europe's 'longest' / Incredible PS13m plan to reopen 'dangerous' UK tunnel that was abandoned 50 years ago / Tolls start dates for London tunnels revealed / The huge 177,000-mile network of secret tunnels that could be 'a treasure' for the UK / The eerie 1.4 mile UK train tunnel that will never be open to the public again / Incredible new live map of UK's secret underground tunnels to save Brits PS2.4billion