Taverny Air Base (formerly Base Aérienne 921 "Frères Mahé" de Taverny) is located in the communities of Taverny and Bessancourt in the Val d'Oise département of France, twenty kilometers north of Paris. Until 2011 it was the headquarters of the French Air Force nuclear strike force, with an underground command center. The base is divided into three tiers with an area of approximately 15 hectares: There were no aviation facilities apart from a heliport.