On a train through the tunnel from Aomori to Hakodate (2014/08/05 22:04:37+09:00) August 9, 2014 1600 × 1066 Asia 2014: Hakodate & Aomori & Sapporo On a train through the tunnel from Aomori to Hakodate (2014/08/05 22:04:37+09:00) Information about the Seikan tunnel: Currently still the world’s longest railway tunnel and longest undersea tunnel.