The document provides a summary of major events that occurred during the 1980s decade. Some of the key events mentioned include:
1) Mt. St. Helens erupted in 1980, blowing down 230 square miles of forest.
2) In 1980, the U.S. men's hockey team defeated Russia in the Olympic semifinals.
3) John Lennon was assassinated outside his New York City home in 1980 by Mark David Chapman.
4) Sandra Day O'Connor became the first female Supreme Court justice in 1981.