The primary tenant is the Denver Broncos of the National Football League (NFL). It opened in 2001 to replace the Broncos original home, the old Mile High Stadium. Empower Field carries on the tradition of the old Mile High Stadium as being one of the most difficult stadiums to play in for opposing teams. Given the difficulty of competing at altitude as well as the notoriously loud fans, the Broncos are known to have one of the best home field advantages in the NFL. Since its opening, the stadium has been home to the Denver Broncos, the Denver Outlaws lacrosse team as well as the Colorado Rapids soccer team. It has also played host to countless concerts and served as the venue for Barack Obama's acceptance of the Democratic nomination to the Presidency.