Sodium chloride, or salt, as it's more commonly known, is essential to life.

The simple ionic compound is necessary for nerve and muscle function, helps regulate fluids in the body, and plays a critical role in controlling blood pressure.

Not having enough salt can cause dehydration, low blood pressure, and even death.

Because of salt's critical importance, it has been pivotal to human civilization.

The humble mineral has been used for millennia in a multitude of ways, from food preservation to religious practices, and became so valuable it carved roads that we still use today.

At one point it was even worth its weight in gold.

This is a history you shouldn't take with a grain of salt.

Let's start in the Paleolithic era.

Humans were still nomadic hunter-gatherers.

They followed animals to naturally occurring salt deposits, also known as salt licks.

Those hunting trails became roads, and people made settlements along those roads.

Now, these early hunter-gatherer societies got all the salt they needed from the meat that they hunted.

But around 12,000 years ago, during what's called the Neolithic Revolution, hunter-gatherers transitioned to agriculture.

The shift away from salt-rich game to more cereal and plant based foods created a dietary need for added salt.

There are two main sources of salt.

The first is evaporated seawater, which leaves behind sea salt crystals.

This includes fleur de sel from the coast of Brittany in France, and Maldon, which is hand harvested in the little English village of the same name.

The second is mineral halite, also known as rock salt.

This can be found deep underground in ancient sea beds that have dried up and crystallized over millennia.

Sometimes those ancient deposits are pushed up through the planet's crust, creating salt domes or even mountain ranges like the Salt Range in Pakistan's Punjab region, where Himalayan salt comes from.

Though the earth is abundant with salt, production in the ancient world was limited to those who lived near seawater, had the resources to mine for deposits deep underground, or seized geopolitical control of those sources.

Now, the interesting thing about the history of salt production is that civilizations around the world figured it out independently from one another.

Roughly 8000 years ago, while people in China's northern province of Shaanxi were collecting salt from Lake Yuncheng, people in Bulgaria's Varna region were harvesting salt from springs in Solnitsata, meaning the salt works.

In 3000 BCE, Ancient Egyptians started gathering salt from marshes along the banks of the Nile, and though they were relatively late to the salt production game, they were among the first to figure out how to use the mineral to cure meats and fish.

And in the Americas, Olmec merchants were already extracting and trading salt along the Gulf Coast as early as 1200 BCE.

As civilizations around the world started figuring out salt production, they began to realize the significant roles it played in everyday life.

Of course, one of salt's most important uses was for food preservation.

It was used to pickle produce and draw bacteria, causing moisture out of meats, which later led to salt cured delicacies like Italian Parma hams and bresaola, as well as Swedish gravlax and bratherring in northern Germany.

Salt was used for medicinal purposes as well.

Pliny the Elder, author of what is considered by many historians as the world's first encyclopedia, Natural History, wrote that salt was used to soothe the belly after childbirth, cure wounds in the eyes of cattle, and help remove wrinkles.

Greek physicians mixed salt into medicines for digestive disorders, ointments to disinfect sores, and prescribed salt for sciatica, tuberculosis, and migraine headaches.

The Mayans mixed salt with marjoram and tree leaves for birth control, and even mixed salt with honey to reduce pain during childbirth.

Salt even made its way into religious practices across many cultures.

It was used in ancient Egypt's mummification rituals, used to protect against evil spirits.

from Asia to Africa, was considered an offering to the gods in ancient Greece and Rome, and in North America salt deities appear in the Navajo, Hopi, and Zuni traditions.

As cultures caught on to the many seemingly magical uses for salt, it became the economic foundation for several empires.

The Chinese were among the first to seize control over salt, building the first ever state controlled monopoly in 700 BCE.

Historians believe that the tax revenue collected from salt helped pay for the Great Wall of China, as well as troops to defend against nomadic tribes like the Xiongnu, Mongols, and Jurchens.

Between the third and fifth centuries, salt accounted for 80% to 90% of state revenues in some of China's kingdoms.

And when Marco Polo visited salt production sites in Yunnan province in the 13th century, he said that people in the mountainous regions, quote, "have none of the Great Khan's paper money, but use salt instead."

For over 2000 years, the only company allowed to sell table salt in mainland China was the China National Salt Industry Corporation, also known as China Salt.

The salt monopoly finally ended in 2017.

The Chinese weren't the only ones to use salt as money.

In 525 BCE, the Empire of Aksum, which is Ethiopia today, used salt bars called amoles as payment, a practice that carried on all the way to the early 20th century.

Moorish merchants in the sub-Sahara traded salt ounce for ounce for gold during the sixth century C.E., and when Hernan Cortez first arrived to the Yucatan Peninsula, he documented that the Mayans had a well established salt industry that included extracting salt from plants, which would be used as currency.

Salt was also crucial to ancient Rome's economy and has left a lasting impression on cultures across Europe today.

Of all the Roman roads that crossed through Europel Via Salaria, the salt road, was among the busiest and parts of it are still in use to this day.

The word salary comes from salarium, which referred to the monthly payment Roman soldiers would receive, part of which was salt.

In fact, sal, the Latin word for salt, still pops up in romantic languages.

Sal is the word for salt in Spanish.

When it's pay day in Spain, you're paid your salario.

And same goes for the French language.

You get a salaire.

So the next time you reach for the salt shaker, take a moment to appreciate the surprising stories behind how this essential ingredient changed the world.

They're stories that stretch back millennia and are deeply intertwined with those of humanity itself.