How many sunken ships sit at the bottom of the sea?

According to World Atlas, at least three million vessels have sunk beneath the waves never to resurface. Many shipwrecks are inaccessible without a submarine, but there are plenty of amazing sunken ships that even rookie divers can explore. Here are a few of our favorites.

USAT Liberty, Indonesia

Credit: mihtiander/iStock

In 1942, an American military transport vessel named USAT Liberty was the target of Japanese torpedoes. At least one torpedo managed to hit its mark, and the ship wound up on a beach on the eastern coast of Bali, Indonesia. Commissioned by the U.S. Navy in Kearny, New Jersey, the first mission of the USAT Liberty was to transport military horses to Europe in the early years of WWII. Afterward, the Liberty was decommissioned and entrusted to the U.S. Shipping Board. This wasn't the end of the mighty vessel's career, however.

Perhaps the USAT Liberty was destined to sink in WWII, but that did not happen until after the 411-foot-long ship was involved in two severe collisions at sea. The first incident, on October 1929, involved a French tugboat, which subsequently sank. Four years later, Liberty collided with an American-owned cargo ship in a shipping channel between New Jersey and the Port of New York.

In 1940, the massive vessel was recommissioned by the US military and set a course for the South Pacific. Mere weeks after the United States entered the war, the USS Liberty was carrying a load of rubber and railway components when a Japanese torpedo struck her broadside. At least two ships tried to tow the damaged vessel to a safe harbor, but the attempt failed. Eventually, the USAT Liberty was deliberately beached and unloaded at Tulamben, Indonesia, where it sat abandoned for decades. In 1963, the eruption of a local volcano pushed the decaying ship offshore.

Today, the sunken USAT Liberty is one of the most popular tourist attractions in Bali. At between 3 and 29 meters deep, the sunken ship is easily viewed from a snorkeler's perspective. Divers who explore the ship's interior are treated to a remarkable display of tropical fauna. They can catch a glimpse of butterflyfish, colorful corals, puffers, and bump head parrotfish, explains Tulamben Wreck Divers.

Cristobal Colon, Bermuda

Credit: Dylan Moulder/iStock

Once a world-class luxury liner, the Cristobal Colon now serves as one of the most exciting dive attractions in Bermuda. Severely damaged by razor-sharp coral when the ship's captain made a miscalculation, the 500-foot-long Spanish cruise ship sank in shallow water off the north shore of Bermuda in October 1936.

As the official story goes, the Cristobal Colon was bound from Mexico to Spain but was turned away by rebels in the Spanish Civil War. The vessel sailed on to France where it was again turned away with 344 passengers aboard. This story may not be factual, however.

According to Bermuda Attractions magazine, the Cristobal Colon may have been en route to Mexico to obtain weapons of war on behalf of the Spanish government. In either case, the ship never completed its journey. The once-mighty Antilla sat broken on a coral reef for years until British bomber pilots used the former cruise ship for target practice.

Today, the wreck field of the Cristobal Colon sits a mere 50 feet below the surface where it is easily explored by snorkelers and persons with basic skills.

Antilla Ghost Ship, Aruba

Credit: LFPuntel/iStock

At 400 feet long, the mostly-sunken ES Antilla is one of the most prominent shipwrecks in the Caribbean. Known to locals as "the ghost ship," the erstwhile cargo carrier was barely one year old when she was scuttled in Dutch–owned waters by her German captain in 1940.

Antilla departed Hamburg, Germany, on July 15, 1939. Her maiden voyage took the vessel to Curacao, then on to Galveston, Texas, where the boat's holds were loaded with sulfur intended for Europe. Plans changed in mid-August when Antilla's captain received an encoded radio message instructing him to return home as soon as possible. Shortly after the news, Germany invaded Poland and Antilla set sail for neutral waters.

Antilla jettisoned her cargo and docked at Aruba. Due to the ship's German heritage, she was closely scrutinized by the Royal Netherlands Navy and was barred from leaving the harbor for several months. In April of 1940, German troops invaded Norway and Denmark, so Dutch officials confined all German sailors to their ships. As Dutch marine forces made plans to board her, the ship's crew set Antilla ablaze. Ultimately, the crew was rescued from the flaming ship before the Netherlands Coast Guard sent Antilla to her watery grave.

Today, the wreck of the Antilla sits in relatively shallow waters where she offers exceptional opportunities for rookie divers, says Fodor's Travel magazine.

Wreck of the San Pedro, Florida Keys

Credit: iStock/negaprion

The 287-ton San Pedro is not the only sunken ship in the Florida Keys, but it's the only one that's a designated Florida state park. At fewer than 20 feet below the ocean surface, the remains of the San Pedro may be explored by snorkelers and divers alike.

As part of Florida's Shipwreck Trail, the San Pedro offers an underwater peek into the past. The vessel embarked from Havana in the summer of 1733, along with 21 other Spanish vessels. Loaded with Mexican silver and priceless Chinese porcelain, the fleet was en route to Spain when a hurricane hit. The San Pedro was ordered back to port, but floundered and sank in the warm waters of Hawk Channel.

In the 1960s, the mostly-intact sunken ship was discovered by treasure hunters who made quick work of salvaging everything they could carry. Cannonballs, ballast, and hardware that remain make this shallow water dive one of the most exciting attractions in the Keys. If you make a dive safari to see this exceptional sunken ship, keep your eyes peeled for colorful reef fish, curious lobsters, tropical anemones, strange tube sponges, and swooping pelicans, advises Visit Aruba magazine.