The Paris Exposition of 1878 presented Yablochkov with the unique opportunity to make a spectacular demonstration for a world audience, and through the promotional efforts of Gramme was successful in having 64 of his arc lights installed along the half mile (0.8 km) length of Avenue de l'Opéra, Place du Théâtre Français (today Place André-Malraux) and around the Place de l'Opéra. It was first lit in February 1878. Yablochkov candles required high voltage, and it was not long before experimenters reported that the arc lights could be powered on a 7-mile (11 km) circuit. Yablochkov candles were superior to Lontin-Serrin regulator arc lights that each required a separate Gramme generator. Beginning in 1880, the Paris Hippodrome's 20 Serrin lights powered by 20 generators were replaced by 68 additional Yablochkov candles, based on two years of positive experience with 60 candles powered by just three generators. The impact of the 1878 Paris demonstration was a depression in the value of gas company shares which did not recover until 1880. French, English, and American businessmen quickly set up companies licensing Yablochkov's patents.