Dive deep into the ultimate submarine quiz!

Humans have always wanted to cruise beneath the waves. Since at least the 16th century, inventors have tinkered with the concept behind submersibles, a basic type of submarine.

Ballast tanks are critical for submarines because they allow the ship's captain to increase or decrease the sub's weight. Water is allowed into the ballast tank to increase weight and stability … and pumped out so that the sub can surface.

When water is pumped out of the ballast tanks, only air remains in the compartments. Air, of course, helps the submarine float thanks to the concept of buoyancy.

The bathyscaphe Trieste was specially designed to withstand the pressure of the deepest ocean. She made it to the bottom of the Challenger Deep in the Mariana Trench.

In the late 1800s, battery technology began transforming the world. Sub designers incorporated (short-lived) batteries as a power source in some of these machines.

Hydroplanes are like wings attached to the backside of the sub. The angle of the hydroplanes alters the sub's course up towards the surface or down into the depths.

Nuclear power generators don’t need air. When you're hundreds of feet beneath the waves, that's a critical factor. It means the sub can travel hundreds of miles without surfacing.

Nazi U-boats were both rugged and deadly, and the Allies knew that they had catching up to do. They copied many U-boat characteristics and integrated them into Allied sub designs.

The USS Nautilus was the world's first nuclear-powered sub. It was launched by the United States in 1954.

Military subs use both active and passive sonar to pinpoint targets. Sonar essentially relies on sound waves that travel through the water.

Cornelis Drebbel, a Dutch seaman and ship builder, constructed the first navigable sub. He built the contraption in 1620.

The vast majority of today's subs are built for military purposes. They are used for spying, defense and for potential offensive strikes, too.

A sub's tower is typically reserved for things like radar equipment and the all-important periscope, which helps the crew peek out of the waves without being spotted by the enemy.

World War II-era subs were still primitive by today's standards. They spent most of their time on the surface, which is where they could most effectively perform their jobs. They dove mostly to escape detection by the enemy.

Cornelis Drebbel was an ambitious man. He reportedly built one sub that carried an amazing 16 people. And during one demonstration, the sub remained underwater for perhaps three hours.

Inventors knew the submarine was going to be a thing. The first submarine patents were granted all the way back in the mid-1700s.

After Drebbel's first subs, it took a while for naval officers to see the potential of the underwater machines. The first military sub didn't appear until 1775.

"The Turtle" was an uninspiring but appropriate name for the first military sub. It looked exactly like an acorn and it was meant to attack British ships during the American Revolution.

The Turtle was meant to help American troops surreptitiously attach explosives to the hulls of British warships. It was a great idea, but it failed on every attempt.

The first subs were propelled by hand-cranked mechanisms, making them not only ugly and unwieldly … but also exhausting.

The Confederates constructed and deployed the H.L. Hunley during the Civil War. The sub sank the USS Housatonic, but suffered catastrophic damage itself and also went to the bottom of the sea.

The H.L. Hunley sank multiple times, drowning many sailors in the process. Each time, the Confederacy raised the ship and tried again. By the time it finally sank for good, surviving sailors were probably glad to be rid of the cursed machine.

The Ictineo II was the world's first steam-powered sub. But the inventor failed to attract investors, so his revolutionary concept never really took off.

The Ictineo II generated steam through chemical reactions. Using potassium chlorate, manganese dioxide and zinc, it heated water into steam, which then propelled the craft.

During World War I, both sides put subs to good use. They played a huge role in the First Battle of the Atlantic, and subs sent countless cargo and military ships to the bottom of the oceans.

Plunging through the pitch-black water, it took the craft about 5 hours to reach the bottom of the Mariana Trench. It took more than 3 hours for the return trip to safety.

Underwater fights versus subs are exceedingly rare. In fact, there's only been a single documented case of two subs duking it out, and it occurred during World War II, when the HMS Venturer sank a German U-boat.

Operation Frigate Bird launched a test nuclear missile, which then denotated in a remote area of the Pacific Ocean. It's the only time that America has detonated a nuke that shot out of a sub.

Most subs favor simplicity in their hull design. They have just one hull. But some subs do have double hulls to add strength to the sub's outer shell and to protect the crew from being drowned.

Modern subs are geared towards stealthiness. If enemies can't detect your subs, they can't stop them, either.