Saturday Trivia

The answer to yesterday's question is:
November 4, 1979. They were held for 444 days, being released on the day President Reagan was inaugurated. President Reagan asked President Carter to greet the former hostages at the hospital in Wiesbaden, Germany, an offer Carter accepted. After medical checkups and debriefings the former hostages were taken to West Point for a hero's welcome.

Today's question is:
What country did the Soviet Union invade in 1979?