According to the Centers for Disease Control and Prevention, Norovirus is the most common cause of stomach problems on cruise ships. The virus is spread by contaminated humans, food and surfaces. It can be hard to control on a cruise ship because of close quarters and sheer number of people and places that might be infected.

The Vessel Sanitation Program, or VSP, inspects ships arriving in U.S. ports and tracks the number of G.I. illnesses reported. They also provide health and safety training to crews.

Though all of these ships were involved in accidents, the Costa Concordia ran aground on a rocky Italian shoreline Jan. 13, 2012. The incident killed at least 28 people.

The MTS Oceanos was a very neglected ship, and it left port on Aug. 3, 1991, with a hole in its watertight bulkhead. This existing problem, combined with an explosion, caused the ship to sink the next day. Besides being one of the biggest maritime disasters in history, it was one of the greatest rescues -- all passengers were saved.

The HMHS Brittanic was the third ship built in the set of sister ships that included the Olympic and the Titanic. It was originally supposed to be named the Gigantic, but they changed the name after the Titanic sunk. Unfortunately, this ship sank, too. On Nov. 12, 1916, an explosion caused the boat to sink in a mere 55 minutes.

Leon Klinghoffer was the only casualty during the hijacking of the Italian cruise ship Achille Lauro in 1984. PLO terrorists took control of the ship and unfortunately, they shot one passenger before they surrendered -- a U.S. citizen named Leon Klinghoffer.

Surprisingly, SOS doesn’t stand for Save Our Ship. Instead, this signal is used because it has a very distinct and recognizable sound in Morse Code.

Here’s a real cruise ship disaster. The Titanic only had two bathtubs for the 700 people in third-class accommodations!

Yes, there was actually talk of trying to lift the wrecked ship by filling it with ping pong balls. They didn’t take into account the fact that the balls would be crushed flat by the water pressure.

Both of these safety measures went into effect after the tragedy. In 1913, the International Ice Patrol started monitoring icebergs in the North Atlantic. In 1914, SOLAS (the International Convention for the Safety of Life at Sea) was created, and has since required that there are enough lifeboats on board to carry all passengers.

Though ship tragedies were plentiful around 1915, the Andrea Doria was rammed by the Swedish MS Stockholm in 1956. All passengers were evacuated, though 46 died as a result of damage to the cabins they were in at the time of the accident.

In 2006, Daniel Dipiero was sailing aboard a Royal Caribbean ship, Mariner of the Seas, when he drank too much and fell overboard as he leaned over the ship’s railing to vomit. After he had been missing for 18 hours, the ship finally checked the video recordings and realized what happened.

In 2007, bacteria was discovered on a Fred Olsen cruise and cut the trip short. A few days after the trip, passenger Robert Heath felt ill and eventually died from Legionnaire’s Disease, which he contracted onboard. The cruise line paid a $100,000 settlement in the case.

Carnival Splendor was the ship that caught fire during a cruise to Mexico. Damage to the engine room resulted in a massive power outage, and the 3,299 passengers had no toilets for 13 hours and had to eat rationed food because food spoiled in the refrigerators.

In 2008, MV Princess of the Stars encountered rough seas en route to Cebu City as a result of Typhoon Frank. The engine stalled and the hull was damaged, so eventually the ship sank.

On July 17, 1918, the Carpathia was sunk by a torpedo from a German U-boat as it steamed around the east coast of Ireland. This was doubly tragic since this ship was famous for helping rescue the Titanic in 1912.

Of course, there are crimes that don’t get reported or are covered up, but many crimes like theft and rape are reported every year and are still tough to prosecute. Because these ships are sailing in international waters, it’s not always clear which laws and penalties apply. So be extra careful when cruising and make safety a top priority.

One of the quickest ways to get kicked off a nightmare cruise is to break one of the ship’s guest policies. Fighting and abusive language are usually on this list. You might end up in the hands of the authorities, but at least you won’t have to endure engine room fires and all-night karaoke.

In an strange accident, a Silversea ship ran into a container ship, nearly capsizing it and crushing its hull. The cruise ship had only minor damages and continued sailing. Now, all of the other ships in port have much more respect for it.

You can’t get all the way though a cruise horror stories quiz without mention of the famous boat that launched the career of Bob Denver! The passengers of the SS Minnow were supposed to be on a short cruise but got caught in a typhoon and were stranded on an uncharted tropical isle. Their trip may have not been a success, but the 7 castaways did enjoy 3 years starring on the hit TV show “Gilligan’s Island.”