RER. In 2006, 920,000 trips took place between Chantilly and Paris-Nord. A small public bus network, Desserte urbaine cantilienne (DUC), links the Lefébure neighborhood to Bois-St-Denis by way of the train station. A branch goes past the château and the Saint-Pierre cemetery. Passengers ride for free. Airports and airport access Chantilly is roughly 30 km from Charles de Gaulle Airport and 54 km from the Beauvais-Tillé Airport. There is no direct route to either by public transportation. An airfield named aérodrome de la Vidamée-Chantilly was opened in 1910 in Courteuil and served as a military air base during World War I. It has since disappeared. Another airfield, known as terrain de Chantilly-Les Aigles, was created during World War II by requisitioning the Les Aigles horse training center in Gouvieux. It was occupied during the Battle of France by the chase group I/1 from the Étampes-Mondésir air base. Trails Two hiking trails cross the commune. The GR 11 circles the greater Paris area and runs between Senlis and Saint Maximin. It cuts through the parc de Sylvie on the château grounds, goes through the Porte Saint-Denis and descends to the Saint-Jean canal, running alongside it until it cuts across the neighborhood known as Coq chantant (Crowing Rooster). The GR 12, which runs from Paris to Amsterdam, goes from Senlis through the south end of town towards the Commelles ponds, then reaches Coye-la-Forêt. The GR 1, known as Tour de Paris, runs along the southeastern edge of town on the south bank of the Commelles ponds. Chantilly Forest is criss-crossed with many paths, which are barred to pedestrians between 6 am and 1 pm, to allow horses to be trained. Chantilly finished a network of bike paths in June 2008 which allow access by bike to Gouvieux, Vineuil-Saint-Firmin et Avilly-Saint-Léonard. Sights The surrounding Chantilly Forest The Château de Chantilly The Chantilly Racecourse The Musée Condé International relations Chantilly is twinned with: Watermael-Boitsfort, Belgium Überlingen, Germany Epsom and Ewell, UK Climate The climate in Val-d'Oise is comparable to that of the northern part of Île-de-France; it has been described as falling somewhere between the oceanic climate of Brest on the coast and the continental climate of Strasbourg. Rainfall is relatively light and with moderately heavy rainfall in spring and early summer, then again in the autumn, which is typical of oceanic climates, but storms are of the continental variety. See also Chantilly lace