The geological process that forms mountains is called orogeny. Orogeny occurs primarily through the collision and convergence of tectonic plates, which can cause the Earth’s crust to fold, fault, and uplift. This process can lead to the formation of various types of mountains, such as fold mountains, fault-block mountains, and volcanic mountains. Significant mountain ranges, like the Himalayas and the Rockies, have been shaped by orogenic events over millions of years. Erosion, climate, and tectonic activity continue to influence the age and appearance of mountain ranges, making them dynamic features of the Earth’s landscape and vital ecosystems.