The global financial markets swung wildly as the EU referendum votes were tallied and released.

After the polls closed at 10 p.m. BST, or 5 p.m. ET, results started to trickle in reflecting a lead for the 'remain' vote. That is, British voters had voted to remain a member of the European Union. This has been the base-case scenario for most experts.

World markets rallied with US stock market futures gaining and the British pound (GBP) surging to a six-month high against the US dollar (USD).

Then the rally collapsed after the vote count from Sunderland was released. According to the count, just 51,930 voted to 'remain' and a whopping 82,000 voted to 'leave.' The vote to leave, or execute a "Brexit," was expected from this district by forecasters. But the margin was so stunningly wide that it raised doubts about the likelihood of the 'remain' vote winning.

Markets tanked

In the hours that followed, more and more votes were tallied and more and more of those votes confirmed that the 'leave' camp had much more support than forecasters and pollsters projected.

And before you knew it, the British pound had tanked to a six-month low. It went from a high of $1.5018 all the way to $1.3777 within a few hours.

Check out this 6-month chart from Bloomberg's Joe Weisenthal.

"Cable did it," Weisenthal said of the GBP/USD currency pair. "It hit a six-month low and a six-month high on the same day."

Reflecting the utter insanity of the evening, by the time this post was published shortly after 11 p.m. ET, the pound crashed through $1.35, its lowest level since 1985!

Meanwhile, stock markets as far as the US markets were not safe. Dow futures were down 560 points and S&P 500 futures were down 70 points.

While the US's direct exposure to the UK is limited, the UK's vote to leave the EU may lead to more instability across Europe, which could eventually turn into a material concern for the US economy and financial markets.

For ongoing coverage of the Brexit vote, follow Yahoo Finance's live blog.

SEE ALSO:

Credit Suisse: The US stock market won't be safe from a 'full Brexit'

Experts warn that the Brexit vote comes with a worse scenario than just the UK leaving the EU

4 recent Brexit-like panic moments that turned out to be total non-events

Here’s everything you need to know about Brexit

3 reasons why the Brexit vote is just not a big deal

Here’s what the Brexit vote could mean for the US stock market