Line 1 is a major subway line in the Paris Métro system, known for its efficiency and extensive coverage. It runs from La Défense in the west to Château de Vincennes in the east, spanning approximately 16.5 kilometers. The line features 25 stations and is one of the busiest in the network, serving millions of passengers each year. Originally opened in 1900, Line 1 has undergone several upgrades, including the introduction of automated trains. It connects key areas of Paris, such as Louvre, Champs-Élysées, and Place de la Bastille, making it a vital transportation route for both locals and tourists.