Was Woodstock the biggest concert in world?

The biggest concert ever held was Copacabana Beach New Year's Eve concert in Rio de Janeiro, Brazil on 31st December 1994, which was attended by an estimated 3.5 million people.

Woodstock was a music festival that was held in Bethel, New York in the United States in August 1969 and is estimated to have had an attendance of 400,000.