Olive oil is the oil pressed from the fruit of the olive tree, a staple cooking fat and flavoring across Mediterranean cuisines for thousands of years. Spain, Italy, and Greece are the world's largest producers today, along with a growing California industry; climate, terroir, and olive variety all shape the finished oil's flavor. Extra virgin olive oil, the least processed grade, is pressed mechanically without heat or chemical solvents and is prized for its intense, complex flavor and aroma; lower grades are more processed and more neutral-tasting. It is used for sautéing, roasting, baking, and as a finishing oil, and is a fundamental ingredient in dishes like Italian pasta, Spanish tapas, Greek salads, and Middle Eastern mezze, pairing well with herbs, citrus, garlic, and balsamic vinegar. It is rich in monounsaturated fat and antioxidants, and is a defining ingredient of the Mediterranean diet.