Milestones

Ten years ago: Leaders of the Group of Seven nations encouraged Soviet President Mikhail S. Gorbachev to enact reforms in return for Western aid.

Five years ago: The United States normalized relations with Vietnam.

One year ago: A U.S. Air Force cargo jet, braving Antarctic winter, swept down over the Amundsen-Scott South Pole Research Center to drop off emergency medical supplies for Dr. Jerri Nielsen, a physician at the center who had discovered a lump in her breast.