In 1978, a group of farmers in a Chinese village called Xiaogang wrote a secret contract and hid it in the roof of a mud hut. They were afraid the document might get them executed. Instead, it wound up completely transforming the Chinese economy.
Many people store water for emergencies — but is it true that water sitting for too long will go bad? Listen in as Marshall Brain breaks down the science of water purification in this HowStuffWorks podcast.