A windshield is the large window at the front of a car, truck, or other vehicle that protects the driver and passengers from wind, rain, insects, and debris while still letting them see where they're going. Before windshields were invented, early car drivers wore goggles and heavy coats because the wind would blast directly into their faces at even modest speeds.

Modern windshields are made from special laminated glass: two layers of glass with a plastic layer sandwiched between them. This design means that if something hits the windshield hard enough to crack it, the glass won't shatter into dangerous flying pieces. Instead, it creates a spiderweb pattern of cracks but stays mostly in place. You've probably seen cars driving around with cracked windshields, waiting to be replaced.

Windshields serve multiple important functions. They're curved to reduce air resistance and help the car move more efficiently. They provide a clear view in rain, thanks to windshield wipers that sweep water away. Many windshields are also treated to resist fog and ice. In modern cars, the windshield is a structural part of the vehicle, helping to keep the roof from collapsing in an accident. That clear piece of glass is working harder than it looks.