Today, September 16, the massive Costa Concordia cruise liner that crashed onto the Italian island of Giglio is finally being pulled off the jagged rocks that snared it. The operation is extremely tense. If any little thing goes wrong, the ship will sink or crumble, destroying the pristine waters there. Engineers have been preparing the ship for 18 months, in the largest marine salvage operation ever attempted. The graphic below explains how they are righting the ship, and how things could go awry (click on it to expand). A written account can be found here, and a live update from Giglio here. Illustration by Don Foley.