Hosni Mubarak had been expected to resign the day before, after 30 years in power. Instead, he delivered a truculent speech insisting he would stay on until September.
But the military had already decided his fate: he would have to go after days of protests had paralysed the country. So just before sunset, the announcement came.
Mubarak was gone, the army was now in control and Cairo exploded in euphoric celebration. Five years later, that day has a dreamlike quality for activists who say they are now living through the darkest times of their lives.
"I was ecstatic," said Mona Seif, a human rights campaigner who was in Tahrir Square that night.
Seif said she knew then that activists like her still had a struggle ahead. But she told AFP she thought "the hardest thing has passed", referring to Mubarak's overthrow.
There are now more activists in prison than at any point during Mubarak's reign. Seif has a brother behind bars -- prominent leftwing activist Alaa Abdel Fattah -- and her sister Sanaa was in jail until being pardoned recently.
Their father, Ahmed Seif, died in 2014 with both children incarcerated. Egypt's preeminent human rights lawyer, he spent his last year alive in courtrooms, trying to free them and other activists.
Alaa and Sanaa were allowed to attend his funeral, but wearing white prison garb.
Egypt is now ruled by another leader who came from the military.
President Abdel Fattah al-Sisi was elected in 2014 after overthrowing the unpopular Islamist president Mohamed Morsi, and unleashing the bloodiest crackdown on dissent in the country's modern history.
Protests that are not approved by the police are banned. Alaa, Sanaa and many other activists were jailed for violating that law.
Hundreds of protesters, mostly Morsi supporters, have been shot dead in the streets, and the government is locked in a war with Islamist jihadists who have killed hundreds of policemen and soldiers.
Reports of police abuses are also on the rise.
Activists who had remained sanguine as the country lurched from one crisis to another after Mubarak's ouster are now reluctant even to talk about that day.
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"No, leave me alone. It's too depressing," one dissident told AFP.
For them, February 11 was not just about removing a dictator, although that in itself had been unimaginable just 18 days previously when the protests began.
It was also about empowerment, social justice and self respect in a country that brimmed with daily humiliations and abuses by corrupt officials and police.
"The nature of despair (now) is so different," said Seif.
"Under Mubarak, you didn't have a lot of hope. But you haven't experienced a moment with the full potential of hope and open space and then the fall down from it."
Timothy Kaldas, a non-resident fellow with the Tahrir Institute for Middle East Policy, was also in the square on February 11 five years ago.
"This is the undoing of what they accomplished," he said of what has happened since.
"What makes it so difficult to stomach and upsetting is not simply that the situation is very bad right now, but the fact that for a brief moment we created an opening, we forced open political space and public discourse."
Heba Morayef, a prominent rights defender who went to Tahrir to celebrate Mubarak's ouster, remembers that day as "pure joy".
But "very soon we were back to doing the usual work as human rights activists".
Rights activists fought abuses and military trials during the interim period of army rule until mid-2012, and then were busy during Morsi's year in power, which was marred by crackdowns on opponents.
Many leftwing dissidents who had led the anti-Mubarak protests supported the massive rallies demanding Morsi's overthrow in the days before his ouster in July 2013.
What confronted them next was a pit of despair in which talk of human rights was practically portrayed as treason by pro-government media.
"I can imagine change in the future, but it's difficult to see change in a positive direction," said Morayef, the associate director of the Egyptian Initiative for Personal Rights.
Despite this, Seif says she will always cherish what she experienced on February 11, 2011.
"Whatever comes, no matter how harsh it is, you can't just go back and regret feeling it."