Syrian forces had been present in Lebanon for 26 years up until that point.
Al-Hariri's death also marked the rise of the March 14 coalition, now led by Saad al-Hariri, the assassinated prime minister's son, named after a day of massive anti-Syrian protests dubbed the "Cedar Revolution".
Reconciliation with Syria
Saad al-Hariri, currently Lebanon's prime minister, has accused Syria of involvement in his father's killing, but he recently reconciled with Damascus, which has always denied accusations that it was behind the bombing.
"We want Syria to take concrete steps, with a deadline, to bring to an end issues that are still hanging between our countries"
head of the Maronite Christian Phalange party
Speaking at the rally on Sunday, he said his visit to Damascus was "part of inter-Arab reconciliation" efforts launched by King Abdullah, the Saudi Arabian monarch.
"I am keen on launching a new phase of ties between Lebanon and Syria as two sovereign, independent countries," he said.
Nisreen el-Shamayleh, Al Jazeera's correspondent, reporting from Beirut, said that this year's rally was markedly different in the wake of that reconciliation.
"This event used to be used as a platform for the March 14 alliance to voice its anti-Syrian sentiments and rhetoric, but that all changed last December when Saad al-Hariri visited Lebanon," she said.
"Hariri's future movement said that they wanted this event to be a unifying one, not a divisive one."
Issues 'still hanging'
But Amin Gemayel, a Hariri ally and the head of the Christian Maronite Phalange Party, said the path to reconciliation with Syria was a long one.
"We want Syria to take concrete steps, with a deadline, to bring to an end issues that are still hanging between our countries," he said.
Elias Atallah, a former MP and one of the first leaders of March 14, told the AFP news agency that the movement had "certainly made mistakes, but we owe it to the people who are here today to keep going".
"There are still a number of aims we have not fulfilled, namely limiting arms in Lebanon to the army, creating stable, sovereign state institutions and seeing the [Hariri] tribunal through."
After years of investigations into al-Hariri's assassination, the Netherlands-based Special Tribunal for Lebanon was formed to try suspects in 2007.
A UN commission of inquiry initially said it had found evidence to implicate Syrian and Lebanese intelligence services, but there are no suspects in custody and Damascus has denied any involvement.