An officer who was supposed to serve on the Titanic's maiden voyage was taken off at the last minute, and took with him the key to a locker in the crow's nest that stored binoculars.
In his haste, second officer David Blair forgot to hand the key over to his replacement and took it with him. As a result, none of the lookouts on board could use the binoculars, despite asking other officers for them.
Fred Fleet, a lookout who survived the disaster, later told the official inquiry that if the crew had had binoculars they would have seen the iceberg the ship struck sooner. When asked by a US senator chairing the inquiry how much sooner, Mr Fleet replied: "Enough to get out of the way."
The 95-year mystery has resurfaced after the key was made available for sale at auction. The key is being sold by Mr Blair's descendants, along with a postcard he wrote to his sister about his disappointment on missing out on the trip. [Link]