Underground Transportation
Underground transportation refers to the system of public transportation that operates beneath the ground level, typically in tunnels or subterranean passageways. This mode of transportation includes subways, metros, underground railways, and other forms of mass transit that provide efficient and convenient travel options for commuters in urban areas. Underground transportation systems are commonly used in large cities around the world to alleviate traffic congestion, reduce pollution, and facilitate the movement of large numbers of people within a limited space.