Also in 1980

• 17 of May - General Chun Doo-hwan of South Korea seizes control of the government and declares martial law in order to suppress student demonstrations.
• 20 of November - Lake Peigneur drains into an underlying salt deposit. A misplaced Texaco oil probe had been drilled into the Diamond Crystal Salt Mine, causing water to flow down into the mine, eroding the edges of the hole.
• 12 of August - The Montevideo Treaty, establishing the Latin American Integration Association, is signed.