Marking the centenary of the Titanic sinking

100 years ago, the ocean liner Titanic - then the largest ship in the world - sailed on her maiden voyage across the Atlantic. Four days into the voyage, on the night of April 14, the ship struck an iceberg and (despite having been described as "virtually unsinkable") rapidly sank, killing over 1,500 of the more than 2,200 passengers and crew on board.

Here we look at the history of the Titanic, and how the anniversary is being marked.