 The TGV system itself extends to neighbouring countries, either directly (Italy, Spain, Belgium, Luxembourg and Germany) or through TGV-derivative networks linking France to Switzerland (Lyria), to Belgium, Germany and the Netherlands (Thalys), as well as to the United Kingdom (Eurostar).Several future lines are planned, including extensions within France and to surrounding countries.Cities such as Tours and Le Mans have become part of a "TGV commuter belt" around Paris; the TGV also serves Charles de Gaulle Airport and Lyon–Saint-Exupéry Airport.