Olive trees are evergreen trees native to the Mediterranean region. They can grow up to 30 feet tall and have silvery-green leaves that are narrow and elongated. The trees are known for their gnarled trunks and can live for hundreds of years, with some specimens believed to be over a thousand years old. The primary product of olive trees is olives, which are small, oval fruits that can be green or black depending on their ripeness. Olives are harvested for their oil, known as olive oil, which is a staple in cooking and has numerous health benefits.