What’sTheHarm is designed to make a point about the dangers of not thinking critically. Namely that you can easily be injured or killed by neglecting this important skill. – At last glance, the casualties, injuries, and cost of not thinking critically came to:
368,379 people killed, 306,096 injured and over $2,815,931,000 in economic damages
The website is operated by Tim Farley, who also does a segment on the Skepticality Podcast on History relevant to skeptics.
It’s a number that can only get bigger, and is far from exhaustive – I would suggest that it barely scratches the surface. Check out the topics available:
Supernatural & Paranormal