The Metropolitan Line is a major railway line in the London Underground network, connecting the city to the northwest suburbs. It runs from Aldgate in central London to Chesham and Amersham in Buckinghamshire, covering a distance of approximately 40 miles. The line serves several key stations, including Baker Street and Harrow-on-the-Hill, and is known for its distinctive deep-level and surface sections. Opened in 1863, the Metropolitan Line is one of the oldest underground lines in the world. It was initially designed to facilitate travel between London and its surrounding areas, playing a crucial role in the development of suburban transport. Today, it remains an essential part of the Transport for London system, providing vital connections for commuters and visitors alike.