It has been exactly one year since House Speaker Nancy Pelosi, D-Calif., announced the start of a formal impeachment inquiry into President Trump.

On Sept., 24, 2019, Pelosi held a press conference at which she announced the House would begin officially investigating the president over a July 2019 phone call between Trump and Ukrainian President Volodymyr Zelensky.

"This week, the president has admitted to asking the president of Ukraine to take actions which would benefit him politically," Pelosi said. "Therefore, today, I'm announcing the House of Representatives is moving forward with an official impeachment inquiry. I'm directing our six committees to proceed with their investigations under that umbrella.

PELOSI ANNOUNCES FORMAL IMPEACHMENT INQUIRY AGAINST TRUMP

"The president must be held accountable," she continued. "No one is above the law."

Some Democrats had grumbled about impeaching Trump essentially since the beginning of his term. But following the whistleblower complaint about Trump's phone call with Zelensky, those calls grew louder within the Democratic caucus. Trump was accused of withholding aid in exchange for political assistance. Pelosi, initially reluctant to open an impeachment inquiry over the Ukraine matter, eventually relented.

Invoking the "darkest days of the American Revolution," Pelosi called on lawmakers to honor their constitutional oath to protect the country "from all enemies, foreign and domestic." House Democrats in recent days have alluded to the possibility they could impeach Trump again, or Attorney General Bill Barr, as a way to block the Senate from confirming a Trump Supreme Court nominee.

During the July 2019 call, Trump allegedly asked for political favors from Zelensky -- specifically an investigation into now-Democratic presidential nominee Joe Biden and his son Hunter, and information about CrowdStrike, a cyber firm used by the Democratic National Committee (DNC) in 2016 to investigate hacking.

"I would like you to do us a favor though because our country has been through a lot and Ukraine knows a lot about it. I would like you to find out what happened with this whole situation with Ukraine, they say Crowdstrike ... I guess you have one of your wealthy people ... The server, they say Ukraine has it," Trump told Zelensky according to a declassified transcript.

Trump later added: "The other thing, there's a lot of talk about Biden's son, that Biden stopped the prosecution and a lot of people want to find out about that so whatever you can do with the attorney general would be great."

In this image from video, presiding officer Supreme Court Chief Justice John Roberts admonishes the impeachment managers and president's counsel in equal terms as he speaks during the impeachment trial against President Donald Trump in the Senate. Roberts, who fastidiously avoids politics, was forced to step into the fray to fulfill his constitutional duty to oversee a Senate impeachment trial earlier this year. (Senate Television via AP)

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Trump at the time of Pelosi's announcement tweeted that the inquiry was "A total Witch Hunt" and "PRESIDENTIAL HARASSMENT!" After months of hearings in the House, Trump was eventually impeached. He was not removed from office, however, as Democratic impeachment managers could not convince enough Senate Republicans to vote to remove the president in January. Only Sen. Mitt Romney, R-Utah, cast a vote to remove Trump from office and it was only on one of the two impeachment articles.

The United States has experienced a uniquely tumultuous year.

Since Pelosi's announcement, a slew of contentious impeachment hearings and interviews roiled Capitol Hill before the House eventually voted to impeach Trump; the United States killed top Iranian General Qassem Soleimani; the Democratic presidential primary process started with severe failures in vote-counting in Iowa; the coronavirus pandemic and a resulting economic crisis upended life throughout the country; race riots and protests have gripped much of the nation in the wake of the death of George Floyd; lawmakers passed multiple trillions of dollars of coronavirus-related economic relief; and now a fight over the Supreme Court seat of late Justice Ruth Bader Ginsburg has broken out just ahead of a presidential election in which both sides are essentially promising litigation.

Fox News' Alex Pappas and Gregg Re contributed to this report.