The Himalayas, Alps, Andes and Appalachian Mountains are examples of fold mountains. The Jura Mountains in Switzerland and France and the Zagros Mountains in Iran and Iraq are also fold mountains.
Fold mountains form when tectonic plates push against each other. The pressure at the junction of these plates increases until the land crumples upward. This process, called orogenesis, created most of the mountains on Earth. Although millions of years old, these mountains are relatively young geologically, and most are still growing. The Himalayas, for example, grow about 1 centimeter per year, and the Elias Mountain Range in North America gains roughly 4 millimeters per year.