Largest, most luxurious, and unsinkable

The largest and most luxurious passenger ship of its time, the R.M.S. Titanic seems to forever hold a place as the most famous shipwreck of popular culture.

Heralded as unsinkable, on April 15, 1912, the ship struck an iceberg, and the Titanic broke apart, sinking 12,000 feet to the bottom of the ocean with more than 1,500 passengers and crew.

During a 2004 expedition, the ROV Hercules is seen here exploring the stern of Titanic, as photographed by its underwater counterpart, ROV Argus, both of which were deployed from the NOAA ship Ronald H. Brown.

The most famous of sunken ships was only just discovered in 1985, and although a few parts have been salvaged, the site remains largely intact.

The 100th anniversary of the sinking of the Titanic is expected to draw an unprecedented amount of commercial shipping traffic to the wreck site, including cruise ships visiting the area, and submersible research expeditions diving to the wreck site, raising concerns.