The stock market just did something it has only done 3 other times in the last 100 years — and...

On Wednesday, stocks got crushed and officially entered a "correction," defined as a 10% drop from recent highs.

This is the second time in the last six months that this has happened — remember, stocks fell 10% in August in just a few days — and these two corrections in such a short period of time don't look good, historically.