The original demarcation line between North Korea and South Korea roughly follows which northern latitude?

I served 16 months there while in the Army. I was assigned to the DMC as a Military Policeman. I visited The Truce Village a Panmunjon. The North has an elaborate building on their side of the border. The building is nothing but a shell and is symbolic. On the conference table in a building that straddles the border is two flags. One for the North and one for the South. The North Korean flag stands just slightly taller than the South. All for show. Meanwhile their poor citizens are starving to death.

Remember this from so many movie scripts.