From ancient civilizations to modern salad dressings, olive oil has been popular for thousands of years.

Olive oil contains monounsaturated fat, which can lower your risk of heart disease by reducing your cholesterol.

It's the only cooking oil that can be harvested by simply pressing fruit.

The term "extra virgin" means the oil is extracted from the first pressing of olives, without chemicals or heat.

Because extra virgin and virgin are less processed, they also contain more heart-healthy antioxidants called polyphenols.

But the compounds get destroyed when the oil is exposed to light.

Speaking of "light," the term refers to the color and flavor of olive oil, not the number of calories.

Olive oil is used not only for cooking, but also soap and skin products.

You can even make lip balm out of it by combining it with beeswax.

In the bible, olive oil was used to anoint the heads of kings, light lamps in the temple, and heal the sick.

In ancient Greece, Hippocrates prescribed olive oil for dozens of ailments including skin rashes, muscle pain and mental health.

Today, Greece consumes more olive oil per person than any other country--more than 6 gallons a year.

The average American is far behind at a quart a year. Still, that's enough to make plenty of salad dressing.