Simplify the following text for a Grade 11 native English-speaking person.
Original: The 2001 event 's success ( 185,000 fans were reported in attendance ) was even more important with the race , then originally held in September , being the largest international sporting event held in the United States after September 11 , 2001 terrorist attacks .
Simplified: It was the largest international sporting event held in the United States after September 11 , 2001 terrorist attacks .