Onions are the most widely cultivated member of the Allium family, far surpassing their cousins such as garlic, leeks, and scallions. Technically, onions are the best-selling vegetable—though tomatoes outsell them, they are botanically classified as fruits, even if they are culturally treated as vegetables.

The scientific name for the onion is Allium cepa, which is derived from Latin words meaning garlic and onion.

Onions have been cultivated for at least 7,000 years. While their exact origin is unknown, it is believed they likely originated somewhere in Central or Western Asia.

The ancient Egyptians essentially worshiped onions, considering them a path to eternal life.

A Roman author named Pliny the Elder believed onions were a cure-all for many ailments, including restless sleep, oral sores, and even dog bites—though most of these beliefs have been disproven. However, onions were indeed used in Roman and Greek medicine with varying degrees of success.

Onions were first introduced to North America by European settlers and were among the earliest foreign crops planted on American soil. Interestingly, the ramp plant—an onion relative—was already native to and used in North America before European arrival.

It is believed that Egyptian laborers were fed in onions, among other crops, during the construction of the Great Pyramids.

The reason people often cry when cutting onions is due to the release of sulfuric compounds, which turn into acid when they reach the eyes.

China is currently the largest producer of onions in the world.

A trick to neutralizing bad onion breath is to chew on parsley, which releases chlorophyll to help freshen the mouth.

Most onions have strong antibacterial properties and have been used in various treatments throughout history. They are low in calories and high in beneficial nutrients.

However, onions are highly toxic to both dogs and cats—much more so than chocolate—even in small amounts.

Vidalia onions can only be grown in specific regions of Georgia, USA, due to the unique soil conditions found there.

Because of their hardiness and ease of cultivation, NASA has considered including onions in potential space farming projects.

Some Native American tribes used onions as trail markers to communicate paths or relay important information to fellow tribe members.