Internet has become a matter of daily routine. It connects people from across the globe. 2016 saw it reaching new limits. Stakes are high in 2017 as well. But,Major technology security firms are warning that hackers are likely to attempt a massive attack on global internet this year. The result could be crippling disruptions in financial markets and critical infrastructure affecting millions.

Late last month, the tech security firm LogRhythm predicted that the internet will go down for at least 24 hours at some point in 2017. And the company’s experts say the impacts of the outage are going to extend far beyond your ability to browse social media.

“In 2017, we’re going to see it hit big sometime, somewhere,” chief information security officer James Carder told Business Insider. “If the internet goes down, financial markets will tank.”

The tech expert said that hackers’ recent targeting of some of the most prominent websites on the internet are likely practice runs for a far broader attack.

“We saw the massive [distributed denial of service] against DynDNS just a couple of months ago,” he said. “That DDoS attack took down sites like Twitter and Spotify for a few hours. We saw a similar DDoS hit Brian Krebs before the attack against Dyn. These were really just tests.

“If you can prove that you can take down massive sites and a large chunk of the US internet for a few hours, a 24-hour outage seems pretty easy to do.”

Other cybersecurity experts are warning that hackers are interested in far more than causing internet disruptions and financial turmoil.

Targeted cyber-attacks on the 700 large power transformers throughout the nation could leavye large swaths of the U.S. in the dark for weeks. And, according to the Government Accountability Office, a hacker acting alone or on behalf of a terrorist organization could cause transformer failure and mass power outages with little more than a laptop.

Internet infrastructure and the electrical power grid are both prime targets for hackers and terrorists. And as technology becomes a bigger part of everything we do, the two are becoming increasingly entwined. That means knocking out large swaths of the U.S. power grid would lead to massive internet disruptions. Likewise, in many cases internet disruptions can cripple the technologically advanced systems upon which major power suppliers rely.