100 years

11:30am on April 11, 1912 sees the Titanic riding anchor 2 miles out from Queenstown (now Cobh, Ireland) harbor while additional passengers board (120 total) and others (7) disembark.

At 1:30 pm, Titanic's starboard anchor is raised for the last time as she departs for her first trans-Atlantic crossing.

 

This is the last known (surviving) photograph of Titanic as she leaves Queenstown harbor. The photo was taken by Fr. Francis Browne, an Irish Jesuit priest who sailed with the ship for the first leg of its journey, from Southampton, England, to Cobh, Ireland, then called Queenstown. 

He would have stayed for the remainder of the transatlantic journey, too, having received an offer of a ticket from a wealthy family he befriended while on board. However, when Browne reached Cobh, he received a note from his clerical superior, ordering him to return to his station immediately rather than sail on. Browne disembarked. 

An enthusiastic amateur photographer (who had received his first camera from the same uncle who later bought him his ticket for the Titanic trip), he brought with him the only photos of the Titanic at sea that would survive the shipwreck.