The dates were announced yesterday for the US leg of Rihanna's "Last Girl on Earth" tour. The 25 date trek will kick off July 2nd in Seattle, Washington and wrap up August 25th in Chicago, Illinois. Opening the shows for Rihanna will be up-and-coming pop star Ke$ha and Lil' Wayne's protege Nicki Minaj. Click Here for a complete list of the dates.