Watch VideoPlay Video
Also on the 65th anniversary of the end of World War Two, South Korea's President Lee Myung-bak sent strong signals to its northern neighbor, by urging Pyongyang to abandon its military provocations in a call for reunification.
The South Korean President says the South and the North cannot continue their history of mistrust and confrontation.
Lee Myung-bak, South Korean President, said, "The North must never venture to carry out another provocation, now will we tolerate it if they do so again. ... It is about time Pyongyang looked straight at reality, made a courageous change and came up with a drastic decision."
Lee Myung-bak proposed a three-stage unification. The two sides would first form a peace community involving denuclearization on the peninsula, then an economic community for cross-border economic integration, and eventually a community of the Korean nation with no institutional barriers.
Close to the border at Imjingak, activists launched balloons loaded with propaganda leaflets, to be carried north by the wind.
And not far away, Christians held an open-air service dedicated to reunification.
There was no immediate reaction from the DPRK to Lee's proposal.
Relations between the two sides are at their lowest point in years, following the sinking in March of a South Korean warship.
The DPRK still denies attacking the Cheonan, and has recently vowed to expand its nuclear arsenal in protest.