The “Iron Curtain” is a metaphor which then Prime Minister, Winston Churchill said in a speech on March 5, 1946.
The term “Iron Curtain” referred to the barrier (divide) put up by the Communist Soviet Union between itself and western, non-communist democratic countries.
The Communist Soviet Union had decided to put up barriers after World War II.
The farmers in Sumer created levees to hold back the floods from their fields and cut canals to channel river water to the fields. The use of levees and canals is called irrigation, another Sumerian invention