 Complete the following phrase:  Upon the release of I Am... World Tour, it received mixed to positive reviews from music critics who generally praised the high-energy performances of the songs as well as Beyoncés vocals. I Am... World Tour debuted at number one on the US Top Music Videos, giving Beyoncé her second consecutive and third non-consecutive number-one DVD in the United States. It was certified double platinum by the Recording Industry Association of America RIAA. The album was also successful worldwide, peaking within the top ten on the DVD charts in every country after its release. It became the best-selling video album worldwide of 2010 and seventh of 2011. I Am... World Tour was nominated for a Grammy Award for Best Long Form Music Video at the 