This weekend i was driving from my house into town and i noticed that without my sunglasses i could not see through the windows of a car in front of me, but then i put my shades on and all of a sudden. . . i could see through the windows perfectly clear. I then realized that this was because the lenses on my sunglasses are polarized. A polarized lens is a lens that blocks out all waves of light that move in a certain direction (vertical, or horizontal ). 
Because my lenses allowed me to see into a vertical object like a windshield that means my lenses are horizontally polarized which only allow light in which is moving in a horizontal direction. This in turn block out all the glare that reflects off of vertical surfaces such as windshields and windows.
