In this underwater photo released by the Italian Coast Guard Monday, Jan. 16, 2012 a breach is seen

Divers are hurrying as quickly as possible to rescue any possible remaining survivors from the Coasta Concordia cruise ship that ran aground off the coast of Tuscany, Italy on Saturday and keeled over.
On Monday, the head of the Italian Coast Guard said there were at least 29 people still unaccounted for -- a sharp increase from previous estimates -- according to CNN . Among the missing are two Americans.
bus tours ireland Speleologists, as they are known, bus tours ireland are used to diving in dark and enclosed spaces. The ship's hallways, cabins and dining rooms are similar to caves -- but caves do not have floating furniture or doors that may be jammed shut.
Some have drawn comparisons to the infamous Titanic disaster and this crash off the coast of Italy, as many of the survivors described their ordeal, having to crawl through long almost vertical hallways and stairwells, the AP writes . Whether that comparison is fair remains a subject of debate.
In this underwater photo taken on Jan. 13 and released by the Italian bus tours ireland Coast Guard Monday, Jan. 16, 2012 a scuba diver swims next to the cruise ship Costa Concordia, after it ran aground near the tiny Tuscan island of Giglio, Italy. Italian rescue officials say a passenger's body has been found in the wreckage of the Costa Concordia cruise ship, raising to six the number of confirmed dead in the disaster. Sixteen people remain unaccounted-for. (AP Photo/Italian Coast Guard, ho)
In this underwater photo released by the Italian bus tours ireland Coast Guard Monday, Jan. 16, 2012 the cruise ship Costa Concordia leans on its side, after it ran aground off the tiny Tuscan island of Isola del Giglio, Italy. The Costa Concordia ran aground on Friday after colliding with a rock. (AP Photo/Italian Coast Guard, ho)
In this underwater photo released by the Italian Coast Guard Monday, Jan. 16, 2012 the cruise ship Costa Concordia leans on its side, after it ran aground off the tiny Tuscan island of Isola del Giglio, Italy. The Costa Concordia ran aground on Friday after colliding with a rock. (AP Photo/Italian Coast Guard, ho)
In this underwater photo released by the Italian Coast Guard Monday, Jan. 16, 2012 the cruise bus tours ireland ship Costa Concordia leans on its side, after it ran aground off the tiny Tuscan island of Isola del Giglio, Italy. The Costa Concordia ran aground on Friday after colliding with a rock. (AP Photo/Italian Coast Guard, ho)
In this underwater photo released by the Italian Coast Guard Monday, Jan. 16, 2012 the cruise ship Costa Concordia leans on its side, after it ran aground off the tiny Tuscan bus tours ireland island of Isola del Giglio, Italy. The Costa Concordia ran aground on Friday after colliding with a rock. (AP Photo/Italian Coast Guard, ho)
In this underwater photo released by the Italian Coast Guard Monday, Jan. 16, 2012 the cruise ship Costa Concordia leans on its side, after it ran aground near the tiny Tuscan island of Isola del Giglio, Italy. (AP Photo/Italian Coast Guard, ho)
In this underwater photo released by the Italian Coast Guard Monday, Jan. 16, 2012 the cruise ship Costa Concordia leans on its side, after it ran aground near the tiny Tuscan island of Isola del Giglio, Italy. (AP Photo/Italian Coast Guard, ho)
In this underwater photo taken on Jan. 13 and released by the Italian Coast Guard Monday, Jan. 16, 2012 a view of the cruise ship Costa Concordia, after it ran aground near the tiny Tuscan island of Giglio, Italy. Italian rescue officials say a passenger's bus tours ireland body has been found in the wreckage of the Costa Concordia cruise ship, raising to six the number of confirmed dead in the disaster. Sixteen people remain unaccounted-for. (AP Photo/Italian Coast Guard, ho)
In this underwater photo taken on Jan. 13 and released by the Italian Coast Guard Monday, Jan. 16, 2012 a scuba diver swims next to the body of the cruise ship Costa Concordia, after it ran aground near the tiny Tuscan island of Giglio, Italy. Italian rescue officials say a passenger's body has been found in the wreckage of the Costa Concordia cruise ship, raising to six the number of confirmed dead in the disaster. Sixteen people remain unaccounted-for. (AP Photo/Italian Coast Guard, ho)
In this underwater photo taken on Jan. 13 and released by the Italian Coast Guard Monday, Jan. 16, 2012 a view of the cruise ship Costa Concordia, after it ran aground bus tours ireland near the tiny Tuscan island of Giglio, Italy. Italian rescue officials say a passenger's body has been found in the wreckage of the Costa Concordia cruise ship, raising to six the number of confirmed dead in the disaster. Sixteen people remain unaccounted-for. (AP Photo/Italian Coast Guard, ho)
In this underwater photo released by the Italian Coast Guard Monday, Jan. 16, 2012 a breach bus tours ireland is seen on the body of the cruise ship Costa Concordia Monday after it run aground bus tours ireland off the tiny Tuscan island of Giglio, Italy. Italian rescue officials say a passenger's body has been found in the wreckage of the Costa Concordia cruise ship, raising to six the number of confirmed dead in the disaster. Sixteen people remain unaccounted-for. (AP Photo/Italian Coast Guard, bus tours ireland ho)
In this underwater photo released by the Italian Coast Guard Monday, Jan. 16, 2012 a breach is seen on the body of the cruise ship Costa Concordia Monday after it run aground off the tiny Tuscan island of Giglio, Italy. Italian rescue officials say a passenger's body has been found in the wreckage of the Costa Concordia cruise ship, raising to six the number of confirmed dead in the disaster. Sixteen people remain unaccounted-for. (AP Photo/Italian Coast Guard, ho)
In this underwater photo released by the Italian Coast Guard Monday, Jan. 16, 2012 a scuba diver swims inside the cruise ship Costa Concordia, Monday, Jan. 16, 2012 after it run aground off the tiny Tuscan island of Giglio, Italy. Italian rescue officials say a passenger's body has been found in the wreckage of the Costa Concordia cruise ship, raising to six the number of confirmed dead in the disaster. Sixteen people remain unaccounted-for. (AP Photo/Italian Coast Guard, ho)
An oil removal ship near the cruise ship Costa Concordia, leaning on its side, Monday, Jan. 16, 2012, after running aground near the tiny Tuscan island of Giglio, Italy, last Friday night. The rescue operation was called off mid-afternoon Monday after the Costa Concordia shifted a few inches (centimeters) in rough seas. The fear is that if the ship shifts significantly, some 500,000 bus tours ireland gallons of fuel may begin to leak. (AP Photo/Gregorio Borgia)