Dozens of soldiers from both North and South Korea peacefully crossed the demilitarized zone on Wednesday, marking the first time troops have done so peacefully since the creation of the zone in 1948.

These operations were related to the past several months of moves to dismantle guard posts and other facilities along te DMZ borders. Wednesday’s crossings were a formality, allowing one another’s militaries to inspect the closures.

The closures along the DMZ are meant to greatly ease tensions along both sides of the border. This will allow the opening of road and rail links between the Koreas, and once a peace treaty is reached, the dismantling of the DMZ outright.

The US has struggled with improving relations between the two Koreas, and the interest among both nations to sign a peace deal ending the Korean War. The US has said no peace can happen without North Korea scrapping its entire nuclear program first, and that’s expected to take many years. In the interim, they are resisting anything that advances the cause of peace too much.