Tens of thousands of Egyptians took to the streets nationwide yesterday determined to oust Islamist President Mohammed Mursi on the anniversary of his turbulent first year in power.
As the working day ended and the heat of the sun eased, more joined them on the otherwise deserted streets of the capital.
Many are angry at Mursi's Muslim Brotherhood, saying it has hijacked the revolution through a series of electoral victories to monopolise power and push through Islamic law.
Waving national flags, a crowd of about 200,000 had gathered by late afternoon in Cairo's Tahrir Square, seat of the 2011 uprising against Mursi's predecessor Hosni Mubarak.
More than 100,000 were out in the centre of second city Alexandria. Anti-Mursi protests were also being staged in the Nile Delta cities of Mansura, Menuf, Tanta and Mahalla, the canal cities of Suez and Port Said and in Mursi's hometown of Zagazig.
"The people want the ouster of the regime," the opposition protesters chanted, the signature slogan of the 2011 revolt that kicked out Mubarak and brought Mursi to power.
"This is the second revolution and Tahrir is the symbol of the revolution," said carpenter Ibrahim Hammouda, who came from the northern city of Damietta for the protest.
But yesterday's anti-government protests eclipsed their gathering in Cairo's Nasr City neighbourhood.
Police and troops were deployed at key buildings nationwide and the health ministry said hospitals were on high alert in case of violence.
A senior security official said the Suez Canal, the vital waterway connecting the Mediterranean with the Red Sea, was under "maximum security". Banks and most offices closed for the day.
Posters urging people to join anti-Mursi protests sprung up around Cairo, plastered on walls and stuck on car windows, along with "June 30" graffiti.
The week ahead of the showdown has seen eight people, including an American, killed and scores more injured as rival demonstrators clashed. Mursi, previously a senior Muslim Brotherhood leader, is Egypt's first freely elected president, catapulted to power by the 2011 uprising that ended three decades of authoritarian Mubarak rule.
His opponents accuse him of betraying the revolution by concentrating power in Islamist hands and of sending the economy into free fall.
Any attempt to remove him from office, they argue, is a coup against democracy.
Leading opposition figure, Nobel peace laureate Dr Mohamed ElBaradei, urged Mursi "to listen to the people" and quit.
Interviewed by a British newspaper, Mursi repeated his determination to ride out what he sees as an undemocratic attack on his electoral legitimacy.
But he also offered to revise the new, Islamist-inspired constitution, saying clauses on religious authority, which fuelled liberal resentment, were not his choice. Fervent displays of emotion from both camps highlight the deep divisions in the Arab world's most populous country.
The army, which led a tumultuous transition after Mubarak's ouster, has warned it will intervene if there is major unrest.
Since taking office, Mursi has battled with the judiciary, the media and the police.
The economy has nosedived, investment dried up, inflation soared and the vital tourism sector been battered.
Many Egyptians stocked up on food and withdrew cash ahead of yesterday's rallies, and long queues at petrol stations brought some parts of Cairo to a standstill.
Mursi supporters are steadfast in defending his legitimacy.
"We will not allow a coup against the president," senior Brotherhood leader Mohamed al-Beltagui told a Cairo rally.
Demonstrator Kamal Ahmed Kamel echoed him, saying: "It's not just about Mursi, it's about legitimacy and the state. We can't go backwards."
Additional reporting by Reuters