Introduction to JFK Assassination Memorial Plaza: JFK Memorial Plaza was built in June 1970. From a distance, it looks like a boxy, hollow building with no roof, no doors or windows, and is suspended in the air. It consists of 72 suspended white concrete columns forming a square wall, 30 feet high and 50 feet long and wide. Except for a narrow passage on the south and north sides that can only be passed by one person, the inside is Like a "tomb" that is closed and isolated from the world.