In 1986, the Espace Naturel Régional in Lille earmarked 10 million francs to develop the site as a tourist attraction for the Nord-Pas-de-Calais region with the intention of establishing a World War II museum there. The plan was publicised in a special open weekend on 20–21 June 1987, attended by over 20,000 people, in which the dome's designer Werner Flos met Professor Reginald Victor Jones, a surviving member of the "Crossbow Committee", at Wizernes. The "Ida" tunnel and side chambers were opened to the public and used for an audio-visual exhibition of the site's history.