200 nuclear weapons'     The US Campaign to Free Mordechai Vanunu   1989 Exxon Valdez oil spill : In Alaska 's Prince William Sound the Exxon Valdez spilled 240,000 barrels (42,000 m³) of oil after running aground. 1990 Indian peacekeeping troops left Sri Lanka. 1998 Jonesboro massacre : In Jonesboro, Arkansas ,