Joining hands and pumping their fists those in attendance sang along to the "Marching for Our Beloved" the iconic anthem of the May 18th Pro-Democracy Movement.
And, President Yoon Suk-yeol led the crowd sing along a first by a conservative president.
His predecessors Lee Myung-bak and Park Geun-hye did not sing leaving participants to choose due to opposition from some conservative groups.
It was only when the liberal president Moon Jae-in took office the song was sung by all participants for the first time in nine years restoring a liberal tradition.
This reflects the still-divided public sentiment surrounding the pro-democracy movement that ended former President Chun Doo-hwan's authoritarian rule.
Some right-wing groups see the protests as an anti-government revolt against Chun successor to the late President Park Chung-hee who's also the father of former president Park Geun-hye.
But Yoon's reversal of the conservative legacy aims to unite the nation backed by his People Power Party which sang in harmony with the liberal Democratic Party.
"I'm so touched. It took us some time to finally make this change, but I hope this is a change that's irreversible."
The DP acknowledges the significance in bipartisan cooperation but called for more efforts.
"We hope the two parties work together to enshrine the spirit into the Constitution. It's a shame that the President reviewed the matter but failed to make any remarks about it during his speech today."
The night before, DP's former presidential candidate Lee Jae-myung who serves as the party's election commission chief paid tribute at the National Cemetery in Gwangju to drum up support ahead of the June 1st local elections and by-elections.
Lee Kyung-eun, Arirang News.