"Freedom! Sovereignty! Independence!" shouted the young and old, rallying on Monday under a sea of waving flags.
At least 70,000 people - some estimates put the figure at 100,000 or even double that number - thronged downtown Beirut, buoyed by their success in forcing the resignation of the government exactly a week ago in a demonstration of 25,000.
Most of the crowd waved Lebanon's red and white flag, distinctive with the green cedar tree in the centre.
"Syria out!" was the most regular cry. Many also raised photographs of former prime minister Rafiq al-Hariri, whose assassination three weeks ago triggered the angry, though peaceful, protests that the anti-Syrian opposition dubbed an "independence uprising."
Show of unity
Many Lebanese have blamed Damascus and their own country's pro-Syrian government for the assassination. Both governments deny such accusations.
The demonstrators repeatedly sang Lebanon's national anthem. Some carried flags or placards imprinted with a crescent and a cross in a show of unity among Lebanon's religious groups. One group raised a banner that read, "Today we have one target: To liberate our land."
The demonstrations will not stop "until we get what we want", said Hannah Farshukh, a 49-year-old woman dressed in black with a blue sticker reading "The Truth" stuck to her chest. "We want to know who killed Hariri and we want the Syrians to get out and leave us alone."
The crowd included a number of die-hard protesters who have been camping out at Martyrs' Square, homemakers, men who took the day off from work, university students and others who travelled from other areas of the country.
In a jab at Syrian President Bashar al-Asad, who in a speech on Saturday said television cameras were zooming in closely on the Lebanese protesters to make the numbers appear more, several held banners reading: "Zoom Out!" One legislator speaking to the crowd yelled out the same phrase during her speech.
Lebanese television stations broadcasting the demonstration regularly panned out, showing the continually growing crowd from wide angles.
Site of bombing
The protesters later marched towards the site of the bomb blast that killed al-Hariri and 17 others.
A group of marchers carried pictures of Lebanon's top security chiefs - including outgoing Justice Minister Adnan al-Qaddum and Major-General Jamil Sayyid, the head of Lebanon's general security department - whom the opposition have urged to resign, accusing them of negligence. "Just go!" was written on the signs.
Butrus Harb, an opposition lawmaker, told the demonstrators: "God willing, today they will decide to leave our country. We want nothing except independence."
Solange Jimayil, widow of slain president-elect Bashir Jimayil, had a message for Lebanese President Emile Lahud and al-Asad: "The Lebanese people will accept nothing less than a full withdrawal. So don't try to play games," she said as she mingled with the protesters.
Jimayil's husband, killed in a 1982 bombing at a Beirut hall, was among a series of political leaders who were assassinated during and after Lebanon's 1975-90 civil war. "I see these young people and I feel such pride," she said.
The three-hour protest passed peacefully, despite heavy military and police presence.
Hizb Allah protest
Syria has been under intense pressure to withdraw its army from Lebanon. Many in Lebanon are sceptical about whether the Syrians would stage a complete pullout.
Hizb Allah called a protest to show loyalty to Syria in central Beirut for Tuesday, apparently to show that not all Lebanese were against Syria. Loudspeakers in villages and towns in Shia areas of southern and eastern regions of Lebanon were urged late on Monday to head to Beirut for the protest.