Donald Trump and Hillary Clinton were busy on the campaign trail, early voting was already underway handful of states and anticipation was building for the second presidential debate, which was two days away.

But by the end of the day, three unprecedented events unfolded that, in remarkably unpredictable ways, would change the course of American history. The Trump campaign seemed to be on the brink of collapse, the US had declared that Russia was trying to interfere in the election, and WikiLeaks began injecting new controversies into the campaign.

The shocking soundbites revealed in the "Access Hollywood" tape, where Donald Trump spoke crudely about groping women, changed the way that many voters felt about him as a person. Though he maintained enough support to win the election, Trump still scores low marks on trust and temperament.

One year later, the impact of Russian meddling is still being assessed. Special Counsel Robert Mueller is investigating whether any Trump campaign associates coordinated with Russia as part of this effort. Three congressional committees are also investigating how the Russians interfered in the election.

Here is a breakdown of what happened that day, and what it all means, with benefit of hindsight.

US officially blames Russia for DNC hacks

The press release hit reporters' inboxes around 3:30 p.m. ET, and it seemed like the kind of bombshell that would carry the rest of the day, and probably into the weekend: The Obama administration was breaking its silence and accusing the Russian government of meddling in the presidential election.

The landmark statement was jointly released by the Office of the Director of National Intelligence, run by James Clapper, and the Department of Homeland Security, led by Jeh Johnson. Both Obama appointees have since testified at congressional committees investigating Russian meddling.

The statement blamed Russia for hacking the Democratic National Committee, and orchestrating the public release of thousands of its internal emails. The disclosures by WikiLeaks roiled the presidential campaign and threw the Democratic Party into chaos, creating bad blood between supporters of Democratic nominee Clinton and runner-up Sen. Bernie Sanders.

"The U.S. Intelligence Community is confident that the Russian Government directed the recent compromises of e-mails from US persons and institutions, including from US political organizations," it said. "...These thefts and disclosures are intended to interfere with the US election process."

Though it wasn't clear at the time, the statement also revealed that a Russian entity was behind recent efforts to scan election systems in "some states" for cyber vulnerabilities. The US intelligence community doesn't think any vote tallies were altered, but senior cybersecurity officials acknowledged this year that Russian-linked hackers targeted 21 states. The states were informed in September.

Considering the sensitivity of the announcement, some have criticized the Obama administration for putting out a brief written statement instead of pursuing a more forceful approach. Clinton wrote in her campaign memoir that she wonders "what would have happened if President Obama had made a televised address to the nation in the fall of 2016 warning that our democracy was under attack."

JUST WATCHED Trump, Clinton spar over DNC hacks Replay More Videos ... MUST WATCH Trump, Clinton spar over DNC hacks 00:55

Shocking 'Access Hollywood' tape reveals vulgar Trump comments

About 30 minutes later came one of the most consequential stories of the presidential election.

The Washington Post published a video from 2005 of Trump speaking in explicit and vulgar terms about groping and kissing women, bragging about what sounded to most people like sexual assault.

"You know, I'm automatically attracted to beautiful -- I just start kissing them," Trump said, speaking on a hot microphone with TV personality Billy Bush for an "Access Hollywood" taping. "It's like a magnet. Just kiss. I don't even wait. And when you're a star, they let you do it. You can do anything. Grab them by the pussy."

Trump recorded on hot microphone having extremely lewd conversation about women in 2005.https://t.co/JV3A9oBJ7c — David Fahrenthold (@Fahrenthold) October 7, 2016

Within minutes, the footage careened around the Internet. It was replayed over and over, sometimes even with uncensored expletives and crude sexual terms, on all the television news networks.

Republican governors, senators and other officials started to publicly condemn Trump's remarks. Some in competitive races across the country further distanced themselves from the GOP nominee, and others even withdrew their endorsements. The Trump campaign was plunged into complete chaos.

"Trump went around the room and asked people the percentages he thought of still winning," Steve Bannon, chief executive of the Trump campaign at the time, recently told CBS News. "(Then-Republican National Committee chairman) Reince (Priebus) said, 'You have two choices. You either drop out right now, or you lose by the biggest landslide in American political history.'"

CNN exit polls found that 70% of all voters were bothered by the way Trump treated women.

Almost a third of people who said it bothered them voted for him anyway.

JUST WATCHED What to bleep, what to air Replay More Videos ... MUST WATCH What to bleep, what to air 08:41

Podesta email leaks start

The third major story broke around 4:30 p.m., when WikiLeaks began tweeting links to emails hacked from the personal account of Clinton campaign chairman John Podesta. By this point in the afternoon, the explosive Trump tape was commanding wall-to-wall attention in the media, so the Podesta leaks were somewhat of an afterthought. But they kicked off weeks of anguish for the Clinton campaign.

What came out on October 7 was the first batch of near-daily releases that were published in the closing weeks of the presidential election. The 20,000 pages of emails were embarrassing for Clinton -- they contained transcripts of her paid speeches to Wall Street banks, controversial comments from staffers about Catholic voters, and messages that appeared to show a cozy relationship with the press.

The Trump campaign latched onto the new releases, and Trump regularly read from the leaked documents at his campaign events. "I love WikiLeaks," he declared at an October 10 rally in Pennsylvania.

Even though the Podesta leaks started coming out about an hour after the US government said Russia had hacked the DNC, it wasn't definitively known at the time that Russia was responsible for the Podesta emails. The US intelligence community blamed Russia in a public report released in January

Podesta himself has speculated that the timing of WikiLeaks' release might be connected to the other major stories that day, though no evidence has emerged to lend any credibility to this argument.

"Let's go through the chronology," Podesta told NBC News about one month after the election. "On October 7, the Access Hollywood tapes comes out. One hour later, WikiLeaks starts dropping my emails into the public. One could say that those things might not have been a coincidence."