Sister

http://www.telegraph.co.uk/news/worldnews/africaandindianocean/seychelles/9108902/Costa-Concordias-sister-ship-adrift-off-Seychelles-after-fire.html

Allegra means "lively" or even "gay" (as in happy) and to me, points again to Viva la Vida (long live life.)

The "long live" theme really seems strong lately.  But it refers to a replacement of power - one had a good, long life, now it's someone else's turn to take power.  At least, this is the way I see it and is at least partly the meaning of the Coldplay song, Viva la Vida.

The bells theme fits perfectly with this as well.  As do drownings, ships/boat, Queen Elizabeth etc.