A streetlight is a tall post with a lamp at the top that lights up roads and sidewalks after dark. Cities install streetlights along streets, in parking lots, and in public spaces so people can see where they're going at night and feel safer walking around.

Before streetlights, cities were pitch black after sunset except for whatever moonlight or starlight might be shining. People carried lanterns or torches if they needed to go out. The first public streetlights burned whale oil or gas in the 1800s, and someone had to light each one by hand every evening. Modern streetlights use electricity and often turn on automatically when the sun sets, using a sensor that detects darkness.

You've probably noticed that older streetlights glow orange or yellow, while newer ones shine with a bright white light. That's because cities are switching to LED bulbs, which use less electricity and last longer than the old sodium vapor lamps.

Streetlights do more than help people see. They also make neighborhoods safer by reducing crime and preventing accidents. Studies show that well-lit streets have fewer car crashes and discourage theft. When you see streetlights flickering on at dusk, you're watching a simple but crucial piece of infrastructure that helps communities function after dark.