It was just another July day when Frau Troffea began to dance a jive in the streets of Strasbourg. Onlookers apparently laughed and clapped at her energy and joie de vivre.

It soon became clear that this was not a simple case of high spirits, however. Frau Troffea continued to dance, and dance, and dance, without rest, for six solid days. Within a week, 34 people had joined her; by the end of the month, 400. At the height of the dancing mania, 15 residents were dying each day from strokes, heart attacks, and sheer exhaustion.

In a valiant attempt to fight fire with fire, the town officials tried to cure the outburst by hiring musicians and building a huge stage in the hope that the mania would soon burn out. Unfortunately, they simply encouraged more people to join the craze.

Watch the video above, produced by our colleagues at BritLab, to find out how the town eventually kicked off its dancing shoes, and the potential causes of one of the oddest medical cases in history.

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