Humma Kavula (played by John Malkovich in the movie) is a semi-insane missionary living amongst the Jatravartid people of Viltvodle VI, and a former space pirate. He seems to be a religious leader on that planet, preaching about the Coming of the Great White Handkerchief. Hence, his sermons end with the words "Bless You" rather than "Amen" as all the Jatravartids sneeze simultaneously at the end of a 'prayer'.
The interiors of Humma Kavula temple were filmed at The Freemasons Hall in London.

Bonus fact: while the Jatravartids were mentioned in the books, the character of Humma Kavula was created by Adams for the 2005 movie.

Photo: Eluveitie