Simplify the following text for a Grade 9 native English-speaking person.
Original: The 1904 Summer Olympics , officially known as the Games of the III Olympiad , was an international multi-sport event which was celebrated in St. Louis , Missouri , in the United States from 1 July 1904 , to November 23 , 1904 , at what is now known as Francis Field on the campus of Washington University in St. Louis .
Simplified: The 1904 Summer Olympics , officially known as the Games of the III Olympiad , were held in St. Louis , Missouri in the United States from July 1 , 1904 to November 23 , 1904 , at what is now known as Francis Field on the campus of Washington University in St. Louis .