In Argenteuil, Val-d’Oise, the covered alley of Les Déserts captivates visitors and sparks curiosity alike. This Neolithic megalithic monument, once discreet and now on the verge of reopening to the public, unveils a lesser-known chapter of Île-de-France’s prehistoric history. A collective tomb over 4,000 years old just a stone’s throw from Paris: an visit that promises a journey back in time.