Hundreds of thousands of people have gathered in Beirut to mark the first anniversary of the killing of former Lebanese Prime Minister Rafik Hariri.
Many in the crowd called for President Emile Lahoud to quit
A throng of red and white Lebanese flags greeted his son, Saad Hariri, who spoke in Martyrs' Square.
Rafik Hariri's death in a truck bombing on 14 February 2005 prompted huge street protests and the withdrawal of Syrian forces stationed in Lebanon.
A UN probe has implicated Syria in the attack, which Syria strongly denies.
Saad Hariri has told the BBC he is confident his father's killers will be brought to justice.
He spoke from behind a glass screen, having returned to Lebanon after spending six months in self-imposed exile.
"As Lebanese, rather than Christians and Muslims, let us cry 'Lebanon First'," he told the cheering crowd.
Banners among the marchers commemorate other politicians and journalists who have died in a series of bomb attacks since Hariri's killing.
Some among the mixed crowd of religious and secular Lebanese shouted slogans against the Mukhabarat, the once-feared Syrian intelligence service that has now left the country.
Speaking to the BBC ahead of the rally, Saad Hariri said he had "full confidence" in the United Nations investigation into his father's death.
"I believe they are professional, they have done a good job and I think that they will one day come out with the truth and the people who killed Rafik Hariri will pay for the crime they committed," he said.
He said the Lebanese people now faced a struggle to "preserve this democracy, this freedom that we got, this sovereignty that we fought for".
But correspondents say much of the idealism that fired Lebanon's early protests against Syria appears to have given way to disillusion and anxiety.
Despite the departure of Syrian forces, the bomb blasts for which they have been widely blamed have continued.
The BBC's Kim Ghattas, in Martyrs' Square, says the Lebanese people want to see the government take responsibility for security in their country.
The attacks - in which Syria denies involvement - have targeted prominent Lebanese critics of Damascus, including journalists and politicians.
Call for unity
Posters have been put up across Beirut commemorating the former leader, whom many credit with rebuilding the Lebanese economy shattered by 15 years of civil war.
Schools and all public and private institutions are closed for the day.
Supporters of the Hezbollah militia, regarded as an ally of Syria, as well as backers of the maverick Christian politician, Michel Aoun, are not taking part in the anniversary rallies.
Many Lebanese still mourn Rafik Hariri, a year after his death
Both groups have argued that the commemoration of Hariri's death has been politicised.
Saad Hariri urged "all Lebanese to adopt a historic position of unity" on the day of the anniversary.
A coalition of anti-Syrian parties led by him won national elections in Lebanon last year.
Early findings by a UN investigation into the killing of Rafik Hariri have implicated top security officials in Damascus and their allies in Lebanon.