Mieskuoro Huutajat Biography (Wikipedia)
Mieskuoro Huutajat (Men's Choir Shouters) is an internationally famous shouting choir from Oulu, Finland. They were established in 1987 and originally comprised 20 shouting men, since expanded to 30.
Led by conductor Petri Sirviö, the choir is best known for their loud renditions of Finnish patriotic songs, but have also performed foreign tunes such as The Star-Spangled Banner.  
They were guest performers at Congratulations, a special 50th anniversary concert for the Eurovision Song Contest held in Copenhagen, Denmark in October, 2005, at which they performed Waterloo. Co-host Renars Kaupers suggested jokingly that perhaps Finland's notoriously poor performances at Eurovision in future could be remedied by the choir performing their own songs. This suggestion was somewhat ironic, as Finland won the subsequent contest.
The performances show some similarities to the traditional Māori's haka war cries.
Mieskuoro Huutajat Tracks