![7 Mysterious Mass Illnesses That Defied Explanation](https://ic-cdn.flipboard.com/history.com/2fe7d03f2f56977a965960d45aa07d78a61641f0/_xlarge.jpeg)
From a dancing plague to a laughing epidemic, the symptoms were clear—but the culprit was not. Mass sociogenic illness—also known as mass hysteria, …
* View the article originally published here. ** More curations: Al Cannistra at San Antonio ONE here.