In 1926, five years after winning the Nobel Prize in Physics, Albert Einstein read a news story about the death of a Berlin family, killed by toxic fumes that leaked from a broken seal in their refrigerator.
Dangerous leaks like this were becoming an alarmingly frequent occurrence as old-fashioned ice boxes were replaced with modern refrigerators that used poisonous coolants.
Einstein became preoccupied with this tragedy, insisting that a better refrigerator design must be possible. He and former student Leó Szilárd, set out to find one.
They used their knowledge of thermodynamics to produce an absorption refrigerator, a device that drove a combination of safer gases and liquids through three interconnected circuits.
It required only a small pilot light as a heat source and was hermetically sealed and safe, so safe that some experts estimate the casing could last 100 years.