Air Date: Week of July 2, 1999

This week, facts about...the largest advertising sign in history. In 1925, an electric sign for the Citroen car lit up the Eiffel Tower and brightened the City of Lights. These days, artificial outdoor lighting has created a problem for star-gazing people and migrating animals in urban areas.

Transcript

CURWOOD: Seventy-four years ago this week in Paris, the City of Light, the largest electric advertising sign was turned on. The Art Deco work spanned the length of the Eiffel Tower. Designed for the Exhibition of Decorative Arts, the sign had 200,000 electric lights and needed its own power plant. Its message, touting the Citroen automobile, could be seen 24 miles away. And its glow became a harbinger of widespread light pollution. According to the International Dark Sky Association, so-called “urban sky glow” caused by billboard lighting, streetlamps, sports stadiums, and the like, not only obscures our view of the stars, it also interferes with the signals that nature sends to many plants and animals. Consider baby sea turtles, for example. When they hatch at night out of beach sand, they head for the brightest spot, which under natural conditions is the horizon over the sea. Artificial light confuses them, making it harder to find the water in time to avoid predators. Migratory birds are also affected, veering off their normal routes and sometimes crashing into towers and buildings. And to help address this problem, even the world's most famous skyline made some changes. New York's Empire State Building reduces its illumination during migratory bird season. And for this week, that's the Living On Earth Almanac.