More and more cities are switching to LEDs to save money and, ultimately, the planet. But ecologists are worried about this trend. Dr. Chris Kyba explains why on a night walk through Cologne, one of Germany's brightest cities.
More and more cities are switching to LEDs to save money and, ultimately, the planet. But ecologists are worried about this trend. Dr. Chris Kyba explains why on a night walk through Cologne, one of Germany's brightest cities.