Édouard Bénédictus, a French chemist, accidentally knocked a flask off of his desk one day. It fell to the ground, but rather than shattering, it had only cracked. The flask had been filled with plastic cellulose nitrate, or liquid plastic, which had evaporated and left a thin but durable film on the inside. This led Bénédictus to securing the first patent for safety glass, which is most commonly used in vehicle windshields.