His revolutionary fervour diminished by the years that have also turned his dark brown hair white, one of the Iranian student leaders of the 1979 US Embassy takeover says he now regrets the seizure of the diplomatic compound and the 444-day hostage crisis that followed.
Speaking before this week's 40th anniversary of the attack, Ebrahim Asgharzadeh acknowledged the repercussions of the crisis still reverberate as tensions remain high between the US and Iran over Tehran's collapsing nuclear deal with world powers.
Asgharzadeh cautioned others against following in his footsteps, despite the takeover becoming enshrined in hard-line mythology. He also disputed a revisionist history now being offered by supporters of Iran's Revolutionary Guard that they directed the attack, insisting all the blame rested with the Islamist students who let the crisis spin out of control.
"Like Jesus Christ, I bear all the sins on my shoulders," Asgharzadeh said.
At the time, what led to the 1979 takeover remained obscure to Americans who watched in horror as TV newscasts showed Iranian protests at the embassy. Popular anger against the US was rooted in the 1953 CIA-engineered coup that toppled Iran's elected prime minister and cemented the power of Shah Mohammad Reza Pahlavi.
The shah, dying from cancer, fled Iran in February 1979, paving the way for its Islamic Revolution. But for months, Iran faced widespread unrest, allowing chaos like Marxist students briefly seizing the US Embassy.
In this power vacuum, then-President Jimmy Carter allowed the shah to seek medical treatment in New York. That lit the fuse for the November 4, 1979, takeover, though at first the Islamist students argued over which embassy to seize. A student leader named Mahmoud Ahmadinejad, who later became president in 2005, argued they should seize the Soviet Embassy compound in Tehran as leftists had caused political chaos. But the students settled on the US Embassy, hoping to pressure Carter to send the shah back to Iran to stand trial on corruption charges.
"The society was ready for it to happen,"Asgharzadeh, then a 23-year-old engineering student, said.
"Everything happened so fast. We cut off the chains on the embassy's gate. Some of us climbed up the walls and we occupied the embassy compound very fast."
The plan had been simply to stage a sit-in. But the situation soon spun out of their control. Ayatollah Ruhollah Khomeini, the long-exiled Shiite cleric whose return to Iran sparked the revolution, gave his support to the takeover, using it to expand the Islamists' power.
"We, the students, take responsibility for the first 48 hours of the takeover," Asgharzadeh said. "Later, it was out of our hands."
As time went on, it dawned on the naive students that Americans wouldn't join their revolution. While a rescue attempt by the US military would fail and Carter would lose to Ronald Reagan amid the crisis, the US as a whole expressed worry about the hostages by displaying yellow ribbons and counting the days of their captivity.
As the months passed, things only got worse. Asgharzadeh said he thought it would end once the shah left America or with his death in Egypt in July 1980. It didn't.
No-one had courage to resolve the matter, though there was still public support. "Society felt it had slapped America, a superpower, on the mouth and people believed that the takeover proved to America that their democratic revolution had been stabilised."
It hadn't, though. The eight-year Iran-Iraq War would break out. The hostage crisis and later the war boosted the position of hard-liners who sought strict implementation of their version of Islamic beliefs.
"We, the students, take responsibility for the first 48 hours ... Later, it was out of our hands."
Seizing or attacking diplomatic posts remains a tactic of Iranian hard-liners to this day. A mob stormed the British Embassy in Tehran in 2011, another attacked diplomatic posts of Saudi Arabia in 2016, which led to ties being cut between Tehran and Riyadh.
Asgharzadeh has since become a reformist politician and served prison time for his views. He has argued Iran should work toward improving ties with the US, a difficult task amid President Donald Trump's maximalist campaign against Tehran.
"It is too difficult to say when the relations between Tehran and Washington can be restored," Asgharzadeh said. "I do not see any prospect."