Santos built 14 airships in all, of which his diminutive No. 9 was the best-known and most successful. On this personal runabout he challenged a friend’s after-dinner remark that his dirigibles were no more than ‘scientific curiosities’ by flying right into the heart of Paris, landing in the Avenue des Champs-Elysées and mooring it on the railings of his house on the corner of Rue Washington while he went inside for coffee. Thereafter Parisians became quite blasé about the sight of No. 9 parked outside fashionable restaurants or in the grounds of the country houses of Santos’s many friends.