What happens when you roll a giant cruise liner, the length of three football pitches, into the upright position after it has been left to rust in the sea for 20 months? This is the multi-million dollar question that engineers are due to answer today , just outside the little port of Giglio.

Heaving work: Members of the US salvage company Titan and Italian firm Micoperi work at the site of the wreckage of Costa Concordia. The engineers will use a never-before attempted strategy to set the ship upright. Pic/Getty Images