rtokens: The steel-hulled Titanic , thought to be unsinkable , struck an iceberg on April 14 , 1912 , and sank , killing 1,523 of the 2,200 passengers and crew on board .
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tokens: It fell as recovery crews were trying to haul the piece into more shallow water and several of the bags burst and cables snapped , she said .
ltokens: The piece of hull , lifted from the ocean floor by means of several diesel-filled bags , had been stuck about 200 feet ( about 70 metres ) below the water 's surface before it fell , she said .