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The history of salt - Salt was in general use long before the beginning of recorded history. More than 40 kinds of salt were itemized in a treatise on pharmacology published in China around 2700 BC, notes Seasalt. (Photo: Flickr/CC BY-NC-ND 2.0)

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China and salt production - In fact, salt production has been important in China for two millennia. Pictured is an illustration of brine being raised from the bottom of a salt well, printed in the Tiangong Kaiwu encyclopedia of 1637.

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Book of Ezra - The Book of Ezra (pictured) associated accepting salt from an individual with being in that person's service. 

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"Salt of the earth" - Similarly, salt is used as a metaphor in the Bible. Salt and light are images used by Jesus in the Sermon on the Mount. "You are the salt of the earth," Jesus tells his disciples in the New Testament, Matthew 5:13.

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Via Salaria - The Via Salaria was an ancient Roman road in Italy, which derives its name from the Latin word for "salt." The remains of several bridges lie broken across vestiges of the old route. (Photo: Wikimedia/CC BY 3.0)

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Salarium - The Latin word salarium was used to describe the so-called salt money paid to Roman soldiers guarding salt supplies, or patrolling "salt roads." It is the forerunner of the modern English word for "salary."  (Photo: Wikimedia/CC BY-SA 3.0)

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Garum - The Romans manufactured garum (fermented fish sauce) using fish intestines and salt. The condiment was stored in tanks like these at the Baelo Claudia archaeological site, near Cadiz, Spain.

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Salt production in ancient Europe - Over 6,000 years ago, the ancient Bulgarian town of Solnitsata—meaning "The Saltworks" and once located near present-day Provadia— was the site of a key salt-production facility.

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Salt production in medieval Europe - The county of Cheshire, in England, became an important center for salt production. This 1491 engraving shows a couple taking away salt from a mine for use as a valuable food preservative.

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Ghandi Salt March - The Salt March, or Dandi Satyagraha, was a nonviolent act of civil disobedience led by Ghandi in 1930 as a protest against taxation on salt production. 

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Origins of salt - Salt comes from two principal sources: sea water and the sodium chloride mineral halite (pictured)—also known as rock salt. (Photo: Wikimedia/CC BY-SA 4.0)

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Sea salt - Produced entirely through the evaporation of ocean water or water from saltwater lakes, sea salt leaves behind certain trace minerals and elements. These add color and flavor.

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Table salt - Table salt is typically mined from underground salt deposits. More heavily processed to eliminate minerals, table salt also contains an additive to prevent clumping. 

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Processing table salt - However, table salt also has added iodine, an essential nutrient that helps maintain a healthy thyroid.

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The largest salt mine in the world - Canada's Goderich salt mine is the largest underground salt mine in the world. Located 548 m (1,800 ft) under Lake Huron to exploit ancient salt deposits, the mine is as deep as the CN Tower in Toronto is tall.

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Ilha do Sal - Pedra de Lume on Sal, one of the islands of the Cape Verde archipelago, is the site of a former salt mine. In Spanish and Portuguese, "sal" means "salt." (Photo: Flickr/CC BY-NC-ND 2.0)

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Wieliczka Salt Mine - One of Poland's most popular visitor attractions, the mine is a world class monument, top-notch health resort, and a UNESCO World Heritage Site.

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Salt Cathedral of Zipaquirá - This underground functioning church is one of Colombia's more unusual tourist destinations, and a revered place of pilgrimage.

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Saline drip - Saline is an isotonic solution of sodium chloride (salt) in distilled water used to clean wounds and help with dry eyes. Saline solution for intravenous infusion is used to treat dehydration.

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Lake Afrera, Ethiopia - Rock salt has been mined at the hypersaline Lake Afrera in the Danakil Depression for centuries. Here, a salt miner works in the heat as he digs out salt blocks by hand.

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The Dead Sea - Nestling on the borders of Jordan and Israel, the Dead Sea boasts a salinity of nearly 34%. Its density is such that swimming is akin to floating.

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Don Juan Pond, Antarctica - But the saltiest body of water on the planet is a tiny, 10-cm deep pond with a saline content nearing an incredible 44%. The BBC explains more. 

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Preserving food using salt - Salting is a technique for preserving food, a process that goes back centuries. Bacon was already being preserved by salting in ancient Rome, and in the Middle Ages most kitchens included a splendid salting chest.

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Preserving food using salt - Salting fish is still common in  many parts of the world, from the Mediterranean through the Atlantic coast of Europe, Russia, Africa, and Asia.

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Himalayan salt lamps - These are hand-chiseled solid blocks of ancient crystal salts that produce beneficial negative ions through heat generated by a light bulb. (Photo: Flickr/CC BY-SA 2.0)

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Using salt to deice roads - Salt was first used in the US in 1938 to deice roads in New Hampshire. By 1942, a total of 5,000 tons of salt was spread on highways nationwide, according to a study by the Cary Institute.

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"Rubbing salt in the wound" - The phrase "rubbing salt in the wound" comes from the days when salt was rubbed into wounds as an antiseptic. In ancient times, medics would sprinkle wounds with salt in an attempt to fight off infection.

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Salt lick, Italian style - The Cingino Dam in Italy's remote Antrona valley is unique for its fleet-footed resident goats that scale the near vertical dam wall in order to lick salt traces off the bricks of the structure.

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Salar de Uyuni, Bolivia - At 10,582 sq km (4,086 sq mi), Salar de Uyuni is the world's largest salt flat.

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Bonneville Salt Flats - Located in the US State of Utah, the salt flats are famous for hosting land speed events over an area known as the Bonneville Speedway. (Photo: Wikimedia/CC BY 4.0)

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Salt Lake City - The Utah state capital was originally called Great Salt Lake City, after its proximity to the largest saltwater lake in the Western Hemisphere. The word "great" was dropped in 1868.

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Tequila and salt - A shot of tequila is often served with salt and a slice of lime. The salt lessens the "burn" of the alcohol and the sour fruit balances and enhances the flavor.

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Salt in the movies - In the action-thriller 'Salt' (2010) Angelina Jolie plays Evelyn Salt, who is accused of being a Russian agent. The film garnered a, er, sprinkling of positive reviews.

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