President Hosni Mubarak resigned and handed power the military Friday, and Egypt held its biggest party in decades.

“The people have toppled the regime,” chanted protesters, whose 18 days of swelling protests tipped Egypt into a crisis that the autocratic government could not undo.

“This is the happiest day in my generation,” said Ali al-Tayab, a 24-year-old demonstrator who paid tribute to those who died in clashes with police and Mubarak supporters. “To the martyrs, this is your day.”

At a presidential palace in Cairo, where demonstrators had gathered in the thousands, people flashed the V-for-victory sign and shouted, “Be happy, Egyptians, today is a feast” and “He stepped down.”

Many prayed and declared: “God is great.”

Crowds began to move toward Tahrir Square, the scene of massive protests against Mubarak that began on Jan. 25.

It was a day after an exultant crowd had gathered on the square for what they expected would be the president’s televised announcement that he would resign. Instead they were shocked to hear him say he would transfer power to his deputy, but keep the title. Angry and disappointed, hundreds of protesters fanned out across the city on Friday.

Vice President Omar Suleiman then announced that his boss had resigned.

“Finally, we are free,” said 60-year-old Safwan Abou Stat. “From now on, anyone who is going to rule will know that these people are great.”

In some neighborhoods, women on balconies ululated with the joyous tongue-trilling used to mark weddings and births. Some sang the national anthem.

Mohammed el-Masry, who marched to the presidential palace, said he had spent the past two weeks living in the protest encampment at Tahrir Square.

“We are going to Tahrir to celebrate,” he said, weeping with joy. “We made it.”