Milestones

Ten years ago: The candidate of Mexico’s ruling party, Carlos Salinas de Gortari, claimed a “national victory” one day after presidential elections that opponents charged were riddled by fraud.

Five years ago: The Group of Seven nations, on the first day of their economic summit in Tokyo, unveiled a long-sought agreement on world trade.

One year ago: Three days after landing on Mars, the Pathfinder spacecraft yielded what scientists said was unmistakable photographic evidence that colossal floods scoured the Red Planet’s now-barren landscape more than a billion years ago.