Monday, the Dow plunged 22.6%.

It had never happened before.

It's still the biggest one day percentage loss of all time.

That means bigger than the 1929 stock market crash or when trading reopened after the September 11th attacks, or during the financial crisis that almost wiped out the global economy.

Here's how CNN reported Black Monday at the time.

Good evening.

The stock market today crashed the Dow Jones industrials, every other major index breaking records in its plummet downward.

Yep, it was, ah, crash pure and simple.

And it was blamed on a number of factors.

Heightened hostilities in the Persian Gulf.

Fear of higher interest rates.

Ah, five year bull market without a significant correction at all and program trading.

But really the word you heard over and over again this is a panic.

People were panicking.

This'll nose dive was pure investor panic.

We'll panic is the only way to describe what happened on Wall Street today.

Panic.

That's a big part of what separates a crash from just a really bad day on Wall Street when emotion takes over, when trading is no longer call more orderly.

That's when black Monday's air born.

So could it happen again?

Ah, panic is always theoretically possible, but a 22% decline on the Dow.

That's less likely because of circuit breakers first implemented after the Black Monday freefall circuit breakers kick in to halt trading when stocks dive too far too fast.

Think of it as a trading time out, designed to give investors a chance to calm down.

In other words, Thio interrupt a panic and maybe to prevent another black Monday.