Line 4 is a rapid transit line in the Paris Métro system, known for its distinctive green color on maps. It runs from Porte de Clignancourt in the north to Bastille in the south, covering a distance of approximately 7.6 kilometers. The line features 27 stations and connects several important neighborhoods and landmarks in Paris. Opened in 1908, Line 4 has undergone various upgrades and renovations over the years to improve accessibility and efficiency. It is particularly notable for its use of rubber tires on the tracks, which allows for a quieter ride compared to traditional metal wheels.