Simplify the following text for a Grade 11 native English-speaking person.
Original: The 1980 Summer Olympics , officially known as the Games of the XXII Olympiad , was an international multi-sport event celebrated in Moscow in the Soviet Union .
Simplified: The 1980 Summer Olympics , officially known as the Games of the XXII Olympiad , were celebrated in Moscow , Soviet Union from July 19 , through August 3 .