Metro systems are rapid transit networks that operate in urban areas, providing efficient transportation for commuters. They consist of underground or elevated trains that connect various neighborhoods, making it easier for people to travel to work, school, or leisure activities. Cities like New York, London, and Tokyo have extensive metro systems that help reduce traffic congestion and pollution. These systems typically feature multiple lines, each identified by a unique color or number, and have stations strategically placed for easy access. Riders can purchase tickets or use smart cards to board the trains, ensuring a smooth and quick journey across the city.