"One of the busiest airports in Europe, the Roissy-Charles de Gaulle International airport has numerous modes of transportation available from the airport to the Paris city center. The airport is connected through the RER & Metro, TGV, Thalys, Bus, Roissybus, Noctilien (Night bus line), airport shuttles, taxis, limousines, airport car rentals etc. Terminals are connected via the CGDVAL." (Quoted from article)