The search vehicle Argo begins a two-hour descent to the hull of the Titanic in the North Atlantic Ocean.

Two four-story-high reciprocating engines (one of which is pictured here) drove the Titanic's outboard propellers.

Lights from the Mir 2 submersible illuminate the port anchor winch on the foredeck of the sunken Titanic.

An intact glass pane from the window of Captain Edward J. Smith's cabin hangs open on the Titanic, which lies two and a half miles (four kilometers) beneath the North Atlantic Ocean.

The Mir 1 submersible illuminates the bow railing of the Titanic.

A ceramic bowl and other debris from the Titanic litter the floor of the Atlantic Ocean off the coast of Newfoundland.

A hull fragment from the Titanic lies on the ocean floor.

An opening on the starboard side of the ship's hull could be damage from the Titanic's collision with an iceberg on April 14, 1912. About 1,500 people died when the ship sank, breaking in two.