Wreck of the RMS Titanic research. The stern section, which had previously received relatively little attention from explorers, was specifically targeted for analysis. The microbial colonies aboard "Titanic" were also a key focus of investigation. The second expedition, from 27 May – 12 June 2004, saw the return of Robert Ballard to "Titanic" nearly 20 years after he discovered it. The expedition spent 11 days on the wreck, carrying out high-resolution mapping using video and stereoscopic still images. 2005 saw two expeditions to the "Titanic". James Cameron returned for the third and last time to film "Last Mysteries of the Titanic". Another expedition searched for
Wreck of the RMS Titanic eating away at "Titanic"s steel and transformed it into rust since the ship sank, but because of the extra damage caused by visitors, the National Oceanic and Atmospheric Administration estimates that "the hull and structure of the ship may collapse to the ocean floor within the next 50 years." The promenade deck has deteriorated significantly in recent years, partly because of damage caused by submersibles landing on the ship. The mast has almost completely deteriorated and has been stripped of its bell and brass light. Other damage includes a gash on the bow section where block letters once spelled "Titanic",