Answer: 20,000 – 5,000 per side
On 31 December 1999 at the approach of midnight, the entire world saw the tower’s beacon and the sparking lights for the first time.
The beacon, sending out two light beams with a reach of 80 kilometres, is composed of 4 “marine” motorised projectors. They are operated by automatically piloted computer programs. Since their rotation sweep is 90°, they are synchronized to form a double beam in a cross that pivots around 360°.
The xenon 6000 watt lamps were chosen for their longevity, around 1,200 hours. The lamps are cooled to prevent overheating and a heating system is activated when the temperatures drop below zero Centigrade whilst the lights are off.
This beacon resonates the image of Gustave Eiffel’s Tower itself as a universal and symbolic landmark.
The sparkling lights are superimposed over the golden lighting. Made up of 20,000 light bulbs (5,000 per side), they bring the monument to life for 5 minutes every hour on the hour once the Tower has been lit up until 1a.m.
To finalize the show, the gold lights were shut down and only the sparkling lights performed, five minutes of magic never seen before, breathtaking.
The glittering light installation of the year 2000 was not made to last and was replaced in June 2003 by another lighting installation meant to weather a period of 10 years.
The Beacon of the Eiffel Tower
Installing the exterior lights is about as impressive as the lighting itself :
25 mountain climbers for the 5 month installation ;
20,000 special light bulbs (5,000 per side) attached one at a time ;
40 kilometers of strings of light and electrical cords ;
40,000 joints and 80,000 various metallic parts weighing 60 tons ;
230 enclosed lighting fixtures and electrical boxes ;
10,000 m² of safety nets ;
120 kilowatts of power ;
Budget total: 4.55 million euros HT
Read More At the Effle Tower official website