Milan, April 29 -- Strange things happen when Inter Milan plays Barcelona in the Champions League semifinals.

The last time the two teams met in the final four of Europe's elite club competition, in 2010, Barcelona had to make a 15-hour journey by bus to Milan after an ash cloud caused by the eruption of the Icelandic volcano Eyjafjallajokull shut down air space, AP reports.

Barcelona lost that first leg 3-1 and a stout defensive performance by Inter in the return match saw it advance to the final 3-2 on aggregate - where it beat Bayern Munich to clinch a historic treble under Jose Mourinho.

Inter is hoping it won't have to make a similarly arduous journey after an unprecedented blackout brought much of Spain and Portugal to a standsti...