In the 400th episode of Stuff You Should Know, Josh and Chuck take a trip through the morgue and look over the shoulders of the often controversial coroners and medical examiners that open cadavers to determine how someone died. Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

Few numbers have as storied a past as zero. Even fewer have had as great an impact on our ability to understand our universe. Yet zero is a relatively recent arrival in math. Find out all about this surprisingly fascinating number with Chuck and Josh. Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

Coral reefs are the largest organic structures on Earth, yet they're created through a symbiotic relationship between creatures about 3 millimeters long. Learn more about the the world's coral reefs (and how to protect them) in this episode. Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

There aren't many criminal pursuits that are as storied as pickpocketing, and some people fondly reminisce over its heyday. Learn why some consider pickpocketing an art form, how to protect yourself from this art and more in this episode. Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

Floods happen when more water is introduced to an area than can be quickly removed. That's about it, but there's more to floods, what causes them and the havoc they can wreak. Join Josh and Chuck in this super-saturated episode of Stuff You Should Know. Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

Despite worldwide prohibitions, slavery still exists. Slaves are forced or coerced into prostitution or made to work in deplorable factory conditions. Yet there's still debate over how widespread the problem is. Learn about modern slavery in this episode. Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

Perhaps it's the colorful masks or the high-flying, rapid-fire acrobatic moves. Whatever it is, there's something uniquely and particularly entrancing about Mexican wrestling, called lucha libre. Learn more about lucha libre in this episode of SYSK. Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

You know those trails that jets leave in the sky? While science has explained why they happen, plenty of conspiracy theorists believe there's more to it. Join Josh and Chuck as they channel the guys from Stuff They Don't Want You to Know in this episode. Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

There's roughly 500,000 squares miles encompassed in a triangle with points in Miami, Bermuda and San Juan. There shouldn't be anything different about this area, but some people believe it's a hotbed of supernatural activity. Tune in to learn why. Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

The answer is yes, but there's a lot more to traveling to the southernmost continent. Learn why emperor penguins don't make eye contact with humans, which country has the best research station and why the chances of your ship sinking are alarmingly high. Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

When Howard Carter opened Tutankhamen's tomb, some believe he unleashed a curse on everyone associated with his expedition. But there's no such thing as a curse, right? Learn the scientific basis beneath King Tut's curse as Chuck and Josh Meet the Mummy! Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

You may have played with a yo-yo before -- perhaps you've even walked the dog -- but do you know about the physics behind what makes a yo-yo sleep and wake up? Learn all about inertia, angular momentum and the history of the yo-yo in this episode of SYSK. Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

There's a 98 percent chance you're drinking coffee right now. Maybe not, sure, but coffee is ubiquitous - about 80 percent of Americans consume coffee and Brazil alone has 3 billion coffee plants. Learn all about the great black brew in this episode. Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

Chuck and Josh test the limits of their decorum as they explore the physiology of an orgasm. Learn all about this inexplicably taboo subject (including how even women who are paralyzed can experience orgasms) in this episode of Stuff You Should Know. Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

Have you ever wondered why the poinsettia is the official plant of Christmas or why we hang stockings by the chimney with care? Join Chuck and Josh for this very special Christmas episode. Who knows, maybe even St. Nick will make an appearance (he doesn't). Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

Lt. John Pike of the Davis, Calif., police department brought the wrath of the Internet on himself when he casually doused peaceful protestors with pepper spray. Find out what was in the can in this eye-watering episode of Stuff You Should Know. Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

Earthworms come in a wide range of sizes: The average U.S. earthworm is 6 to 11 inches long, and the giant worms of Australia and South America can grow to a length of 11 feet. Join Josh and Chuck as they burrow into the weird world of earthworms. Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

The digestive system uses mechanical and chemical processes to absorb and transport all the nutrients your body needs to survive -- but how does it work? In this episode, Josh and Chuck take you through all 30 feet of the average digestive system. Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

Benjamin Franklin first came up with daylight saving time in 1748, and people still practice it today. But how does it work? What are the pros and cons? Join Josh and Chuck as they turn back the clock to explore the origins of daylight saving time. Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

Sure we take it for granted the elephant represents the Republican party and the donkey Democrats, but have you ever wondered why? Josh and Chuck explore the foundation of these bizarre political symbols in this old-timey episode of Stuff You Should Know. Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

Chuck and Josh take a stab at answering the age old question of whether cash or plastic is the best choice for paying your way through life. Join them as they look at shopping, theft, security and the heartbreak of overdraft fees in this episode. Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

It's been just 300 years since the Thoroughbred breed has been around, but it has produced some of the most storied animals humans have ever loved. Chuck and Josh dive into what makes these horses special and the controversy around racing them. Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

Sure, they look cool. It's as if someone put a bow and a rifle together, but in fact crossbows predate firearms by a few thousand years. Learn all about the advantages crossbows bestow, the physics behind them and how to use one with Josh and Chuck. Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

As you might imagine, the President of the United States doesn't fly coach. But what exactly does he use when traveling from point A to point B, and how does it actually work? join Josh and Chuck as they demystify Air Force One. Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

Sure, you've heard stories about Alcatraz. From high-profile escape attempts to tales of notorious inmates, the Rock is unique in American history. But how did it actually work? Join Josh and Chuck as they explain the Stuff You Should Know about Alcatraz. Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

The first televised Presidential debate had some odd results: The radio audience tended to believe Nixon won, while television viewers supported Kennedy. Today, debates continue weld an enormous influence on public opinion. But how do they work? Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

Should a company be able to own the rights to something found inside your own body? In this episode, Chuck and Josh delve into the complicated, controversial world of gene patents. Tune in to learn more about the history -- and future -- of gene patents. Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

The pre-colonial range of the American bison stretched from Canada to Mexico. From 1820 to 1880, the population dwindled from 30 million to just over 1,000. Join Josh and Chuck as they explore how bison were brought back from the verge of extinction. Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

The autobahn has an international reputation, and people around the world love the notion of driving on a road with no speed limits -- but how true is this reputation? Join Josh and Chuck as they tell you everything you need to know about the autobahn. Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

It's Halloween again, and this year Chuck and Josh are ringing in the holiday with a special reading of the short story "Berenice," by Edgar Allan Poe. Tune in to catch Stuff You Should Know's Poe-rific Halloween episode. Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

There may be a Bizarro World in our universe. Every particle has a mirror image with a reverse electrical charge, and when these opposites meet an energy transfer 300 times stronger than nuclear fusion occurs. Could this reaction power spacecraft? Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

If you live in a place where privacy is protected, the legal system keeps prying eyes from your personal information. But does that privacy extend beyond death? That depends. Tune in to learn more. Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

The Nile River has been flowing south to north for about 30 million years, and the human race's cradle may have been along the Blue Nile stemming from Ethiopia. Find out some amazing facts about what may be the world's most important river. Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

In the 19th century, typhoid was considered a disease of the lower classes. When an outbreak occurred in wealthy Oyster Bay, New York, a mystery was afoot. Tune in to learn how this event began an ongoing debate over public safety versus civil rights. Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

Few riots can be attributed to passing fashions, but zoot suits are top among them. After originating among the Harlem Renaissance crowd, the zoot suit came to symbolize political defiance. Find out why it's still illegal to wear a zoot suit in L.A. Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

Since its inception, the Peace Corps has sent 200,000 members to 193 countries to deliver aid and good will through know-how rather than direct funding. Learn about the successes, criticisms and dangers of the Peace Corps in this gung-ho episode of SYSK. Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

When the Japanese invaded Southeast Asia in World War II, they cut off America's rubber supply. Luckily, American can-do created a synthetic rubber and saved the War. Learn about the inventor, fluid chemistry and more in this episode of SYSK. Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

Thought Chuck and Josh had already covered every law enforcement agency? Think again. The Marshals Service is the oldest law enforcement branch in the land, dating back to 1789. Listen up for how to get a free ride courtesy the Marshals in this episode. Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

Houdini suggested that sword swallowing was merely a trick. But there's no sleight of hand or throat to this ancient practice. Practitioners really do swallow swords, car axles and more. Learn more about sword swallowers in this gag-reflexive episode. Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

After 800 years of creating coats and crests, some meaning has been lost to history, but much has been retained and is still in use. Find out what a mullet on field argent with stags rampant means in this Olde English episode of Stuff You Should Know. Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

Over the course of our lives, 80 percent of us will experience acne. Ultimately, acne comes down to one thing, a blockage in the sebaceous gland. Learn what makes a blackhead black, and everything else about zits, in this pus-filled episode of SYSK. Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

Did you know that science still doesn't know the exact origin of the moon? Do you know how the moon creates high and low tides? Do you know the difference between a waxing crescent and a waning gibbous? You will after listening to this riveting episode. Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

Gambling predates the written word; dice made of bones have been discovered at prehistoric sites. Today, the concept of amassing a fortune in moments remains attractive. Join Josh and Chuck as they take a look at the games and the glitz of casinos. Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

The World Trade Center was once a global symbol of progress. Since the attacks of Sept. 11, the area has undergone a massive rebuilding process. Chuck and Josh take a look at the World Trade Center, its memorial and its symbolism in this special episode. Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

Over the centuries, some scientists have concluded that the best test subject is looking at them in the mirror. Join Josh and Chuck as they explore 10 researchers, unsung or otherwise, who put their own health second to the advancement of science. Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

Instead of actually detecting lies, polygraph machines sense physiological variations, ostensibly brought on by guilt. The results are subject to interpretation, and therefore controversial. Join Josh and Chuck as they investigate the polygraph. Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

In 1964 The Prospect of Immortality laid out a plan for placing humans in suspended animation. The first person was placed in cryonic suspension three years later. But how does it actually work? Learn more about cryonics in this chilly episode of SYSK. Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

Up to 24 million people worldwide have schizophrenia. Despite the vast amounts of research, the disorder remains mysterious. In this episode, Josh and Chuck delve into the nature of schizophrenia, from the history of the disorder to the latest research. Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.